Coast guard and maritime safety aptitude: study guide ##################################################### Rail, transit, road transport, maritime, and logistics · suite apt-371-coast-guard-and-maritime-safety-aptitude · generated 2026-09-15T15:42:41.289Z Title: Coast guard and maritime safety aptitude: study guide Generated: 2026-09-15T15:42:41.289Z Fixture/version: apt-371-coast-guard-and-maritime-safety-aptitude Sector: Rail, transit, road transport, maritime, and logistics Guide version: v2 ! Private practice result. Not an official exam certificate, employer decision, hiring signal, admissions decision, or guaranteed outcome. Scores stay on this device unless you export them. ! Answer keys and scoring logic stay server-side and are never included in any download or export. How to use this guide ===================== This file contains the whole study outline for this suite: every skill it draws on, the full lesson for each of those skills, worked examples, practice tips, a glossary, and where each piece of material comes from. Nothing here is a summary of a page you still have to visit. 1. Read the skills section end to end once, without timing yourself. 2. Work the guided practice mode for the suite, using the practice tips as a checklist. 3. Move to the mini-test only when guided practice feels unhurried. 4. Sit the full simulation last, once, in the conditions you expect on the day. Practice attempts are stored on the device you used, never on an account. Exporting a result is the only way anything leaves that device. Practice modes and durations ============================ Practice modes for Coast guard and maritime safety aptitude Mode Duration What it is for --------------- ---------- ------------------------------------------ Guided practice 15 minutes Untimed, with feedback after every item. Mini-test 18 minutes A short timed set for checking pace. Full simulation 45 minutes Full length and full time, in one sitting. - Start guided practice: https://learn.novusstreamsolutions.com/aptitude/practice/new?bank=apt-371-coast-guard-and-maritime-safety-aptitude&mode=guided - Start mini-test: https://learn.novusstreamsolutions.com/aptitude/practice/new?bank=apt-371-coast-guard-and-maritime-safety-aptitude&mode=mini - Start full simulation: https://learn.novusstreamsolutions.com/aptitude/practice/new?bank=apt-371-coast-guard-and-maritime-safety-aptitude&mode=full Skills covered, in full ======================= This suite draws on 5 skill constructs. Each one below carries its complete lesson. Safety judgment --------------- Hazard recognition, safe sequencing, escalation, and risk controls. Practise recognizing hazards and choosing a safe, proportionate response: protect people, control immediate exposure, use the correct reporting path, and verify that the control is effective. What you should be able to do after this lesson: 1. Separate a hazard from the likelihood, severity, and exposure that shape its risk. 2. Choose an immediate control that stays within the person's training and authority. 3. Recognize when work should pause and when a supervisor, emergency process, or qualified specialist is needed. Worked examples and pitfalls ---------------------------- Worked scenario: a damaged machine guard: A guard is loose before a scheduled run. Do not operate the machine or improvise a repair beyond your authorization. Keep people away, isolate or label the equipment only as procedure permits, report the defect to the responsible person, and wait for an approved inspection or repair. A deadline does not remove the hazard. Risk-triage questions: Ask: what can cause harm, who is exposed now, how severe could the outcome be, what control is available, and who has authority to apply it? The safest answer is not always the most dramatic option; it is the option that controls the real exposure without creating a new hazard. How to practise this skill -------------------------- - Treat warnings, permits, isolation rules, and personal protective equipment as parts of a system, not interchangeable shortcuts. - Do not ask an untrained person to investigate a hazard simply because they are nearby. - In real work, site procedures and qualified safety direction override any general preparation heuristic. Glossary -------- Hazard A source or situation with the potential to cause harm. Risk A judgement about possible harm that considers likelihood, severity, and exposure. Control A measure that removes a hazard or reduces exposure to it under an approved process. Study this next --------------- - Occupational safety and health: https://learn.novusstreamsolutions.com/search?q=Occupational%20safety%20and%20health - Hazard: https://learn.novusstreamsolutions.com/search?q=Hazard - Risk assessment: https://learn.novusstreamsolutions.com/search?q=Risk%20assessment - Safety judgment lesson on Novus Learn: https://learn.novusstreamsolutions.com/aptitude/skills/safety-judgement/lesson Where this material comes from ------------------------------ - Novus Learn original safety-critical, hazard-recognition, and operational suite scenarios. - Novus educational framework: identify the hazard, protect people, control exposure, report, and verify. ! Educational preparation only. Novus Learn does not administer official exams and does not guarantee scores or hiring outcomes. Situational judgment -------------------- Evaluating workplace responses against role-relevant principles. Learn a repeatable way to compare workplace responses: establish the facts, identify duties and risks, respect role boundaries, then choose a proportionate first action. This is educational preparation, not an official scoring guide. What you should be able to do after this lesson: 1. Separate facts stated in a scenario from assumptions that the scenario does not support. 2. Rank response options by immediate risk, policy or role obligations, proportionality, and follow-through. 3. Explain why a strong first action is better than passive, punitive, or unauthorized alternatives. Worked examples and pitfalls ---------------------------- Worked scenario: an unverified safety concern: A colleague reports a possible equipment fault while a deadline is approaching. First distinguish the known fact, the report, from the unverified cause. A strong response protects people and affected work, checks the concern through the right channel, tells the relevant lead, and records what was done. Ignoring the report underreacts; shutting down unrelated work or accusing someone before checking the facts overreacts. Method: facts, duties, risks, response: Write four short notes before ranking options: what is known, who may be affected, which duty or boundary applies, and what safe next step is available now. Prefer an action that addresses the immediate issue and creates useful follow-through. Do not reward an option merely because it sounds decisive. How to practise this skill -------------------------- - Answer the question asked: best first action, worst action, or complete response are different tasks. - Check whether an option acts within the person's authority and escalates only as far as the risk requires. - When two options look reasonable, prefer the one that gathers missing facts and communicates ownership. Glossary -------- Proportionality Matching the urgency and scope of a response to the evidence, likely impact, and authority available. Role boundary The limit of what a person may decide or do without approval, specialist help, or escalation. Follow-through Confirming ownership, recording the decision, and checking that the issue was actually resolved. Study this next --------------- - Situational judgement test: https://learn.novusstreamsolutions.com/search?q=Situational%20judgement%20test - Workplace ethics: https://learn.novusstreamsolutions.com/search?q=Workplace%20ethics - Decision-making: https://learn.novusstreamsolutions.com/search?q=Decision-making - Situational judgment lesson on Novus Learn: https://learn.novusstreamsolutions.com/aptitude/skills/situational-judgement/lesson Where this material comes from ------------------------------ - Novus Learn original situational-judgment suite scenarios and published construct mapping. - Novus educational framework: facts, duties, risks, role boundaries, proportional action, and follow-through. ! Educational preparation only. Novus Learn does not administer official exams and does not guarantee scores or hiring outcomes. Numerical reasoning ------------------- Arithmetic, fractions, percentages, ratios, rates, estimation, word problems, and number relationships. Numerical reasoning is the ability to take a small set of supplied numbers (a price list, a staffing table, a fuel figure), and reach a defensible answer in around ninety seconds without a formula sheet. It is the most widely used quantitative section in graduate, management and public-sector screening, and it appears in banking, retail, armed forces and healthcare entry batteries alike. The arithmetic itself is deliberately ordinary: percentages, ratios, rates and averages. What is actually being measured is whether you pick the right operation quickly, keep the units straight, and answer the question that was asked rather than the one you started computing. Practice here is device-local: no account, and nothing leaves this device unless you export it. What you should be able to do after this lesson: 1. Move between fractions, decimals, percentages and ratios on sight, and pick whichever form makes a given item fastest (12.5 percent as one eighth, 33.3 percent as one third). 2. Apply percentage change in both directions, including recovering an original figure from a post-increase total, and combine successive changes multiplicatively rather than by adding them. 3. Split a total in a stated ratio by counting parts first, and work backwards from a stated difference between two shares. 4. Solve rate problems (speed, unit price, consumption, combined work rates) by carrying units through every intermediate line so the units of the answer prove the method. 5. Produce a one-significant-figure estimate before computing, and use it to eliminate the distractors built from the common wrong operations. 6. Read a multi-step stem and name, in one sentence, the single quantity the final question asks for before touching the numbers. Worked examples and pitfalls ---------------------------- Reverse percentages: the item most candidates get backwards: A subscription price rose by 15 percent and now stands at 57.50 pounds. What was it before? The correct move is to divide, not subtract: the new price is 115 percent of the old, so the old price is 57.50 / 1.15 = 50.00. Check it forwards: 15 percent of 50 is 7.50, and 50 + 7.50 = 57.50. The tempting wrong answer takes 15 percent of the NEW figure, 0.15 x 57.50 = 8.625, and reports 48.88. That distractor is always on the option list because it is what most people do under time pressure, and it is wrong by 2.25 percent, small enough to look plausible. The same asymmetry drives the successive-change item: a price that rises 20 percent and then falls 20 percent does not return to where it started. Multiply the factors: 1.20 x 0.80 = 0.96, a net fall of 4 percent. Starting at 500 pounds you get 600 then 480, not 500. Percentages compose by multiplication; they never add. Ratio splits: count the parts before you divide: A 4,830 pound budget is split between three teams in the ratio 3:5:6. Add the parts first: 3 + 5 + 6 = 14. One part is 4,830 / 14 = 345. The shares are 3 x 345 = 1,035, 5 x 345 = 1,725 and 6 x 345 = 2,070, and they sum back to 4,830, which is the check you should always run. Two classic failures. The first is dividing by 3 because there are three teams. That gives 1,610 each and ignores the ratio entirely. The second is treating 5 as a fraction and computing five sixths or five fourteenths of something other than the total. The more interesting version of this item gives you a difference instead of the total: 'the second team receives 690 pounds more than the first, what is the whole budget?' The difference between the shares is 5 - 3 = 2 parts, so one part is 690 / 2 = 345, and the budget is 14 x 345 = 4,830. Same number, reached from the other end, and the arithmetic is trivial once you have made the parts explicit. Rates and units: 2 h 15 min is 2.25, not 2.15: A delivery van covers 174 km in 2 hours 15 minutes. Average speed is distance over time, and the time must be in hours: 15 minutes is 15/60 = 0.25 h, so 174 / 2.25 = 77.3 km/h. Type 2.15 into the calculator instead and you get 80.9 km/h: an error of roughly 4.7 percent that sits comfortably inside the plausible range and will match one of the options. Now extend it. The van consumes 8.6 litres per 100 km, so the trip needs 174 x 8.6 / 100 = 14.964 litres, and at 1.48 pounds per litre that is 14.964 x 1.48 = 22.15 pounds. Notice the units doing the work: (km) x (L / 100 km) leaves litres; (L) x (pounds / L) leaves pounds. If your intermediate line has km still attached at the end, you have divided when you should have multiplied. Write the unit next to every number and the method checks itself. Unit pricing: normalise before you compare: Three pack sizes of the same fluid. Pack A: 750 ml for 3.60 pounds. Pack B: 2 litres for 9.40. Pack C: 1.5 litres for 7.20. Convert all three to price per litre. A: 3.60 / 0.75 = 4.80 per litre. B: 9.40 / 2 = 4.70. C: 7.20 / 1.5 = 4.80. So B is cheapest by 10p a litre, and A and C are identical despite looking like different deals. The 'bigger pack is cheaper' heuristic happens to hold here but is not a rule, and test writers know it. Half of these items are built specifically so the largest pack loses. Now add the multibuy that these questions love: pack A is on three-for-two. Three packs give 2.25 litres for the price of two, 7.20 pounds, which is 7.20 / 2.25 = 3.20 per litre and beats everything. The trap in the multibuy version is dividing by the number of packs paid for rather than the volume received. Combined work rates: add rates, never times: Printer A completes a 3,000-page run in 50 minutes; printer B completes the same run in 75 minutes. Running together, how long? Convert to rates: A prints 3,000 / 50 = 60 pages per minute, B prints 3,000 / 75 = 40 pages per minute, and together they print 100 pages per minute, so the job takes 3,000 / 100 = 30 minutes. Verify by counting output: in 30 minutes A produces 1,800 pages and B produces 1,200, which is 3,000 exactly. The two wrong answers you will see on the option list are 62.5 minutes (the average of 50 and 75) and 125 minutes (the sum). Both are impossible on inspection: two machines working together must finish faster than the faster machine alone, so any answer above 50 minutes is wrong before you compute anything. The general form is 1 / (1/50 + 1/75), and it is worth being able to write that line directly, but the sanity bound catches the error faster than the algebra does. Estimate first, then compute: killing distractors in ten seconds: 'A department spent 847,300 pounds in 2024. In 2025 the budget fell by 12.5 percent. What was the 2025 spend?' Options: 741,387.50 / 953,212.50 / 105,912.50 / 762,570. Estimate before anything else: 12.5 percent is exactly one eighth, one eighth of roughly 850,000 is roughly 106,000, so the answer is roughly 744,000. That single line eliminates three options. 953,212.50 applied the change upwards. 105,912.50 is the size of the reduction, not the resulting spend: the 'answered the wrong question' distractor, and the most commonly selected wrong option on items of this shape. 762,570 is a 10 percent cut, planted for anyone who misread the rate. Exact working: 847,300 x 7/8 = 5,931,100 / 8 = 741,387.50. Doing it as a fraction avoids the decimal multiplication altogether. Learn the fraction equivalents cold (12.5 percent is 1/8, 16.7 percent is 1/6, 37.5 percent is 3/8, 62.5 percent is 5/8) because a fraction turns most percentage items into one division. How to practise this skill -------------------------- - Memorise the fraction-to-percentage table up to eighths and twelfths. Almost every 'nasty' percentage on these tests is a clean fraction in disguise, and the fraction route is two or three times faster than decimal multiplication. - Write the unit beside every intermediate number, including the ones you keep in your head. Most numerical errors on timed sections are unit errors, not arithmetic errors, and units are the only cheap way to catch them. - Rehearse reverse percentages as their own drill until dividing by 1.15 feels more natural than subtracting 15 percent. It is a single, identifiable technique that accounts for a disproportionate share of lost marks. - Before selecting, re-read the last clause of the stem out loud. 'By how much did it fall' and 'what was it after the fall' have different answers, and both are always on the option list. - Keep an error log with four columns (misread the question, wrong operation, unit slip, arithmetic slip), and tally which one you actually commit. Three sessions is usually enough to show that one column dominates, and that is the column to train. - Work untimed until your method is stable, then add the clock in stages: generous, then realistic, then 20 percent tighter than the real test. Attempts stay on this device, so a slow first pass costs nothing. Glossary -------- Percentage point The arithmetic difference between two percentages. A rate moving from 4 percent to 5 percent rises by one percentage point but by 25 percent in relative terms; questions specify which they want and the two answers are both on the option list. Reverse percentage Recovering an original amount from a figure that already includes a percentage change, by dividing by the multiplier (1.15 for a 15 percent rise, 0.88 for a 12 percent fall) rather than subtracting the percentage from the new figure. Multiplier (decimal factor) The single number a quantity is multiplied by to apply a percentage change: 1.20 for plus 20 percent, 0.80 for minus 20 percent. Successive changes are handled by multiplying the factors, which is why plus 20 then minus 20 gives 0.96, not 1. Ratio part One unit of a ratio split. Dividing the total by the sum of the ratio terms gives the value of one part; every share and every difference between shares is then a whole number of parts. Unit rate A quantity expressed per one of something: price per litre, pages per minute, litres per 100 km. Comparisons are only valid once every option has been converted to the same unit rate. Combined rate The sum of two or more individual rates working simultaneously. Times cannot be added or averaged; only rates add, and the combined time is the total work divided by the combined rate. Significant figure estimate Rounding every input to one meaningful digit to get an approximate answer in a few seconds. Its purpose is not accuracy but elimination: it removes any option that is off by a factor or has the sign of the change wrong. Distractor A wrong option written deliberately to match a specific predictable error: subtracting instead of dividing, reporting the change instead of the result, averaging instead of combining rates. Recognising the pattern is often faster than recomputing. Study this next --------------- - Numerical reasoning skill hub: https://learn.novusstreamsolutions.com/aptitude/skills/numerical-reasoning - Numerical reasoning practice in the Cognitive Skills Lab: https://learn.novusstreamsolutions.com/cognitive-skills/numerical-reasoning - Data interpretation lesson: https://learn.novusstreamsolutions.com/aptitude/skills/data-interpretation/lesson - Office numeracy suite: https://learn.novusstreamsolutions.com/aptitude/tests/office-numeracy - Finance, accounting and insurance careers: https://learn.novusstreamsolutions.com/careers/families/finance-accounting-and-insurance - Numerical reasoning lesson on Novus Learn: https://learn.novusstreamsolutions.com/aptitude/skills/numerical-reasoning/lesson Where this material comes from ------------------------------ - All worked figures above were written and checked for Novus Learn. Every division, ratio split and rate calculation in this lesson was verified by recomputing it in the reverse direction. - Conventions only (percentage point, unit rate, significant figures) cross-checked against standard public references such as the Wikipedia articles 'Percentage', 'Ratio' and 'Rate (mathematics)'. No item text is drawn from any published test. - Novus Learn aptitude construct registry (catalog seed) for construct scope and suite mapping. - Public educational framing only: not affiliated with any official exam board, publisher or employer, and no copyrighted test item is reproduced. ! Educational preparation only. Novus Learn does not administer official exams and does not guarantee scores or hiring outcomes. Map and route reasoning ----------------------- Directions, coordinates, schedules, routes, and navigation constraints. Map and route reasoning is spatial thinking with a clock attached: bearings and turns, map scale, grid references, and the journey-time arithmetic that decides whether a route is feasible at all. It appears in police, fire and ambulance selection, driver and dispatch testing, military navigation batteries, and any logistics or field-service role where a wrong turn is a missed window. The items are rarely hard mathematically; they are lost by rotating the map instead of the number, by averaging two speeds, or by adding a walking leg to the wrong end of a connection. Your practice attempts are stored on this device and go nowhere unless you export them. What you should be able to do after this lesson: 1. Convert any facing into degrees clockwise from north, apply a sequence of left and right turns arithmetically, and convert the result back to a compass point. 2. Compute a back bearing and use it to check that an out-and-return leg is consistent. 3. Convert map distance to ground distance from a ratio scale such as 1:25,000, and say why the ratio has no units. 4. Give and read four-figure and six-figure grid references in the correct order, and state which square or point a reference identifies. 5. Compute door-to-door journey time from distance, average speed and fixed stops, and work backwards from a fixed deadline to a latest departure. 6. Compare candidate routes against stated constraints and identify which constraint actually binds on the vehicle, the load or the time window. Worked examples and pitfalls ---------------------------- Bearings: turn the number, not the map: You are facing north. Turn 90 degrees right and you face 090, east. Turn a further 135 degrees right: 90 + 135 = 225, south-west. Now turn 90 degrees left: 225 - 90 = 135, south-east. The method that survives any number of turns is to hold the facing as a number of degrees clockwise from north, add for right turns, subtract for left turns, take the result modulo 360, and convert back at the end using the eight-point table: 0 north, 45 north-east, 90 east, 135 south-east, 180 south, 225 south-west, 270 west, 315 north-west. Candidates who instead picture themselves rotating lose the left-right convention the moment they are facing south, because on the mental image left now appears on the right of the page. The companion idea is the back bearing: the reverse of a leg is the forward bearing plus or minus 180 degrees, so a leg travelled out on 040 comes home on 220, and a leg out on 250 comes home on 070. Checking that every outbound and return pair differs by exactly 180 catches a dropped turn immediately. Scale: from the sheet to the ground: On a 1:25,000 sheet, one centimetre of paper represents 25,000 centimetres of ground, which is 250 metres. A path measured at 6.4 cm is therefore 6.4 x 250 = 1,600 m, or 1.6 km. Move to a 1:50,000 sheet and the same 6.4 cm becomes 3.2 km, because each centimetre now stands for 500 m. Two mistakes recur. The first is dividing rather than multiplying, which turns a 1.6 km walk into a 26 m one and should be caught instantly by asking whether the answer is plausible for a footpath. The second is forgetting that a ratio scale carries no units: 1:25,000 means one inch to 25,000 inches just as much as one centimetre to 25,000 centimetres, which is exactly why the printed scale bar is safer than a ruler when a sheet mixes conventions. Finally, map distance is horizontal distance. A route that climbs 300 m over that 1.6 km is meaningfully longer and much slower on foot, which is why walking-time estimates add time for ascent separately rather than inflating the distance. Grid references: along the corridor, then up the stairs: On a numbered map grid, the four-figure reference 3572 means easting 35 and northing 72. It identifies a whole one-kilometre square, and specifically the square whose south-west corner sits at that intersection: not its centre. To locate a point inside it, divide the square into tenths in each direction: a feature five tenths east and five tenths north of that corner is 355725 in six figures, which pins the position to roughly 100 m. The two failures are reliable enough to be worth naming. The first is giving northings before eastings, so 7235 gets quoted for a feature that is actually at 3572, pointing at an entirely different square or at nothing at all. The second is treating the reference as the centre of the square, which shifts every reported position by half a kilometre to the north-east. The mnemonic that fixes both is 'along the corridor, then up the stairs': you walk along before you go up, and eastings always come first. Journey time with a stop, and the average-speed trap: A van covers 84 km at an average 56 km/h. Driving time is 84/56 = 1.5 hours, or 90 minutes. Add a 20-minute unload part way and the door-to-door time is 110 minutes, so a 08:20 departure arrives at 10:10. If the receiving bay closes at 10:00, the total budget is only 100 minutes; with the 20-minute stop unavoidable, driving must fit into 80 minutes, and the required average becomes 84 / (80/60) = 63 km/h. That is the shape of most feasibility items: find the fixed time, subtract the fixed stops, and solve for what is left. The trap sits in the word average. Suppose the same 84 km is driven as 42 km at 70 km/h and 42 km at 50 km/h. The mean of the two speeds is 60 km/h, and that is the wrong answer. Add the times instead: 42/70 = 0.60 h and 42/50 = 0.84 h, total 1.44 h, so the true average is 84/1.44 = 58.3 km/h. Average speed is always total distance over total time, never the mean of the speeds. Routing under constraints: find the one that binds: Depot to site, three options. Route A is 18 km and crosses a bridge posted at 7.5 tonnes. Route B is 14 km but the final 300 m is one-way against you, forcing a 1.2 km loop, so it is really 15.2 km. Route C is 16 km and includes 800 m of school zone limited to 20 km/h between 08:00 and 09:00, where you would otherwise do 40 km/h. Your loaded van weighs 3.5 tonnes and you leave at 08:30. Price the constraints. The bridge limit does not bind at all: 3.5 tonnes is well under 7.5, so route A's restriction costs nothing and A is simply the longest at 18 km. The school zone does bind, but barely: 0.8 km at 20 km/h takes 2.4 minutes against 1.2 minutes at 40, a penalty of 1.2 minutes, leaving C at 16 km plus about a minute. Route B, at 15.2 km including its loop, is still the shortest. The trap is choosing A because it is the option with no restriction that applies, a constraint that does not bind is not a cost, and noticing that is precisely what the item measures. Timetables: work backwards from the fixed event: Buses leave the depot at five and thirty-five minutes past each hour. The ride to the station takes 25 minutes, then a 6-minute walk to the platform. Trains depart at 09:12, 09:42 and 10:12. To catch the 09:42, you must be on the platform by 09:42, so the latest boarding time is 09:42 minus 25 minus 6 = 09:11. The 09:05 bus qualifies: it reaches the station at 09:30 and the platform at 09:36, six minutes clear. The 08:35 bus is on the platform at 09:06 and would also make the 09:12 with a little to spare. The 09:35 bus reaches the platform at 10:06 and can only make the 10:12. The two errors that cost marks are subtracting the walking time from the wrong end (adding it to the train departure instead of the bus arrival, which manufactures twelve minutes of slack that does not exist), and reading a timetable's arrival column as though it were the connection's departure. Fix the deadline first, list every fixed time in one column, then choose. How to practise this skill -------------------------- - Convert every facing to degrees clockwise from north before you do anything else. Arithmetic on a number survives a question that turns you round four times; mental rotation does not. - Never rotate the paper. Rotating the map reverses your left and right the instant the route heads south, and that single habit accounts for a large share of lost bearing marks. - Write the scale conversion once at the top of the page, '1 cm = 250 m', and reuse it for the whole set. Recomputing it per item is where factor-of-ten errors are born. - For timetable items, work backwards from the fixed deadline and write every fixed time in a single column before you look at the options. Forward-adding invites you to forget the walk or the changeover. - Never average two speeds. Add the times, then divide total distance by total time. The arithmetic mean of the speeds is almost always one of the offered answers, and it is there deliberately. - When a route question lists a restriction, ask explicitly whether it binds on this vehicle, this load and this departure time. Practise untimed until spotting a non-binding constraint is automatic; attempts stay on this device, so repetition costs nothing. Glossary -------- Bearing A direction given as degrees measured clockwise from north, conventionally written with three digits so that east is 090 and south-west is 225. Back bearing The bearing of the return leg, equal to the forward bearing plus 180 degrees if it is under 180, or minus 180 if it is over. A leg out on 040 returns on 220. Ratio scale A unitless map scale such as 1:25,000, meaning one unit measured on the sheet represents 25,000 of the same units on the ground, whatever unit you choose. Easting and northing The horizontal and vertical grid coordinates of a position. Eastings are always quoted first, which is what the 'along the corridor, then up the stairs' mnemonic encodes. Six-figure grid reference A four-figure square reference refined by tenths in each direction, locating a point to roughly 100 m rather than to a one-kilometre square. Dead reckoning Fixing a position from a known starting point plus the recorded headings, speeds and elapsed times, without any external fix to correct the accumulated error. Average speed Total distance divided by total elapsed time. When a question asks door to door, the elapsed time includes every stop, not only the time in motion. Contour interval The fixed height difference between adjacent contour lines. Tightly spaced contours mean steep ground, and therefore a journey time longer than the flat map distance suggests. Connection time The interval between an arrival and the next scheduled departure, including any walk or transfer. It is the constraint that actually decides most timetable items. Study this next --------------- - Cognitive Skills Lab: map and route practice: https://learn.novusstreamsolutions.com/cognitive-skills/map-route-reasoning - Map and route reasoning skill hub: https://learn.novusstreamsolutions.com/aptitude/skills/map-route-reasoning - Route and timetable reasoning suite: https://learn.novusstreamsolutions.com/aptitude/tests/route-and-timetable-reasoning - Supply chain, transport and logistics careers: https://learn.novusstreamsolutions.com/careers/families/supply-chain-transport-and-logistics - Spatial reasoning lesson: https://learn.novusstreamsolutions.com/aptitude/skills/spatial-reasoning/lesson - Map and route reasoning lesson on Novus Learn: https://learn.novusstreamsolutions.com/aptitude/skills/map-route-reasoning/lesson Where this material comes from ------------------------------ - Navigation and scheduling examples computed for Novus Learn from first principles: clockwise bearing arithmetic, ratio-scale conversion, grid-reference convention, and distance-speed-time with fixed stops. - Terminology checked against the public Wikipedia articles 'Bearing (navigation)', 'Scale (map)', 'Ordnance Survey National Grid' and 'Dead reckoning'. Definitions only; every route, timetable and figure above is original. - Novus Learn aptitude construct registry (catalog seed) for the construct scope and related suite mapping. - Public educational framing only: not affiliated with any official exam board, publisher or employer, and no copyrighted map extract or timetable is reproduced. ! Educational preparation only. Novus Learn does not administer official exams and does not guarantee scores or hiring outcomes. Critical thinking ----------------- Evaluating evidence, assumptions, arguments, credibility, and alternative explanations. Critical thinking assessments ask you to take an argument apart: what is being concluded, what it rests on, what evidence would settle it, and whether a proposed conclusion actually follows. Published critical-thinking batteries typically run five task types - inference, recognition of assumptions, deduction, interpretation, and evaluation of arguments - and they are deliberately built so that agreeing with a conclusion and judging the argument as strong come apart. The construct is heavily weighted in policy analysis, audit, legal, investigative and graduate selection, and it is the same skill that stops a plausible chart from turning into a bad decision. Practice stays on this device; there is no account and nothing is uploaded unless you export it. What you should be able to do after this lesson: 1. State an argument's conclusion in your own words before evaluating it, and identify which sentences are premises and which are background. 2. Use the negation test to separate a required assumption from a statement that would merely strengthen the argument. 3. Distinguish validity from truth, and identify affirming the consequent as distinct from the valid modus tollens form. 4. Compute a posterior probability on a screening example and explain why the rate of true positives among all positives is far lower than intuition suggests. 5. Generate at least two alternative explanations - selection, reverse causation, a common third factor - for any claimed causal effect, and name the comparison that would rule them out. 6. Judge argument strength on relevance and directness rather than on agreement, including marking arguments you personally reject as strong. Worked examples and pitfalls ---------------------------- The negation test finds assumptions; nothing else does: Argument: 'The council should fit bin sensors across the district. In the trial depot they cut collection trips by a fifth.' Candidate assumption A: 'The trial depot's waste pattern is broadly representative of the rest of the district.' Negate it - suppose the trial depot is nothing like the rest of the district - and the argument collapses, because a result that does not transfer supports nothing about the district. So A is a required assumption. Candidate assumption B: 'Bin sensors are the cheapest available technology for this purpose.' Negate it - suppose they are the most expensive - and the argument still stands as given, since it argued from a reduction in trips, not from cost. B is not required; it would strengthen a cost-based argument that was never made. Candidate C: 'Fewer collection trips reduce total operating cost.' Negate it and the recommendation loses its point, so C is required too, even though the argument never mentions cost. That last case is the one candidates miss, because the required assumption is what bridges the evidence to the recommendation, and bridging assumptions are by definition unstated. The failure mode across this whole item type is picking statements that support the conclusion instead of statements the argument cannot survive without. Base rates: 90 percent accurate, 15 percent right: A production line runs an automated defect test. Defects occur in 1 percent of units. The test flags 90 percent of genuinely defective units, and wrongly flags 5 percent of good units. A unit has just been flagged - how likely is it to be defective? Work in whole units rather than probabilities. Take 10,000 units: 100 are defective and 9,900 are good. Of the 100 defective, the test flags 90. Of the 9,900 good, it wrongly flags 5 percent, which is 495. Total flags: 90 + 495 = 585. Of those, 90 are genuine, so the answer is 90 / 585 = 15.4 percent. Better than the 1 percent base rate, and nowhere near the 90 percent that intuition offers. The error has a name - confusing the probability of a flag given a defect with the probability of a defect given a flag - and it has a practical consequence: the rework queue has to be sized for 585 units a batch, not 100, and 495 of the 585 units sitting in it are perfectly good. Whenever a test, screening rule or model accuracy figure appears in an item, ask how many of the negatives there are, because with a rare condition the false positives from a large clean population swamp the true positives from a small affected one. Three alternative explanations, and the comparison that settles it: Claim: 'Employees who attended the optional resilience workshop took 30 percent fewer sick days last year, so the workshop works.' Alternative one, selection: attendance was optional, so the people who signed up may have been the healthier and more engaged to begin with, and would have taken fewer sick days regardless. Alternative two, reverse direction: employees who were frequently unwell were the least able to attend a full-day workshop, so illness determined attendance rather than the other way round. Alternative three, a common third factor: the workshop ran on Thursday afternoons at head office, so attendance largely tracks being an office-based rather than shift-based worker, and shift workers take more sick leave for reasons that have nothing to do with resilience training. What would settle it: randomly assigning the offer to half the workforce and comparing the two groups. Failing that, the cheapest useful check already exists in the payroll data - compare attendees' and non-attendees' sick days in the year before the workshop. If attendees were already 30 percent lower, selection is doing the entire job. The habit worth building is to name the comparison group before you accept any before-and-after number. Deduction: affirming the consequent versus modus tollens: Rule: 'If an invoice is over 10,000 euro, it requires two signatures.' Argument A: 'This invoice has two signatures, therefore it is over 10,000 euro.' Invalid - this is affirming the consequent. The rule makes two signatures necessary for large invoices; it says nothing that prevents a cautious manager from double-signing a 400 euro invoice, so a two-signature invoice of any size is consistent with the rule. Argument B: 'This invoice has only one signature, therefore it is not over 10,000 euro.' Valid - this is modus tollens, denying the consequent to deny the antecedent, and it holds assuming the rule was followed. Argument C: 'This invoice is not over 10,000 euro, therefore it does not have two signatures.' Invalid again, denying the antecedent. Two further points that deduction items test directly. First, validity is about form alone: 'All banks close on Sundays; Riverton Mutual is a bank; therefore Riverton Mutual closes on Sundays' is perfectly valid even if the first premise is false, and a valid argument with a false premise can deliver a false conclusion. Second, in these items you must accept the premises as given even when you know them to be untrue, because the question is whether the conclusion follows, not whether it is true. Interpretation: what a survey figure does and does not license: Data: all 1,200 employees of a firm were surveyed. 62 percent said they would accept a four-day week at 90 percent pay. Of those who said yes, 71 percent were under 35. Conclusion one: 'A majority of this firm's employees would accept the trade.' This follows - 62 percent of a complete census of the firm is a majority, and the conclusion is properly limited to this firm. Conclusion two: 'A majority of the firm's under-35 employees would accept the trade.' This does not follow, and the arithmetic shows why. Sixty-two percent of 1,200 is 744 accepters, and 71 percent of 744 is about 528 accepters aged under 35. That is the composition of the accepters, not the acceptance rate within the under-35 group, and without knowing how many under-35s the firm employs the rate is undetermined: if there are 900, the rate is 528 / 900 = 59 percent; if there are 600, it is 88 percent; if there were 1,100 the rate would be below half. Conclusion three: 'The firm should move to a four-day week.' This does not follow either - a stated preference about pay says nothing about output, shift cover, customer hours or cost. Notice that conclusion two is the base-rate error from the screening example, wearing survey clothing. Strong and weak arguments on the same question: Question: should the agency publish raw inspection scores for every site? Strong argument for: 'In the neighbouring authority, publication was followed by a measurable fall in repeat violations, which is the stated aim of the inspection regime.' It is directly about this decision, it addresses the regime's own objective, and it offers evidence - and if true it would change your view. Weak argument for: 'Yes, because transparency is always good.' Sweeping, unsupported, and it would apply identically to publishing anything at all, which is the tell. Strong argument against: 'Raw scores omit the severity weighting, so a site with one critical failure can rank above a site with six minor ones, and a member of the public cannot see the difference.' Specific, mechanistic, directly about the proposal, and it would change your view. Weak argument against: 'No, because businesses will object.' It may be true and it may matter politically, but it does not bear on whether publication achieves the regime's aim, and no evidence is offered. Two tests separate strong from weak: is the argument about the exact question asked, and would accepting it change the decision? Note that you can hold a firm personal view on publication and still be required to mark the argument on the other side as the strong one - that split is what the item type is measuring. How to practise this skill -------------------------- - Negate every candidate assumption out loud. If the argument survives the negation, it was never an assumption, however supportive it sounds. This single habit converts the assumption item type from guesswork into a mechanical check. - Write the conclusion in your own words before reading any option. Half of the wrong answers on inference and evaluation items are responses to a conclusion the argument never reached. - Ask 'percentage of what?' on every percentage in the stimulus and reconstruct the denominator in whole units. Base-rate and composition errors both dissolve the moment you write out counts instead of rates. - Deliberately practise marking arguments you disagree with as strong and arguments you agree with as weak. Assessments in this construct are built to catch agreement masquerading as evaluation, and the effect is largest on politically loaded stimuli. - For any causal claim, write two alternatives - selection and a third factor - and name the comparison group that would rule them out, before you decide whether the evidence supports the claim. - Log wrong answers by task type rather than by topic: inference, assumption, deduction, interpretation, evaluation. Candidates are rarely weak across all five, and the profile tells you where the next hour of practice belongs. Glossary -------- Conclusion The claim an argument is trying to establish. It is not always last, is often signalled by therefore, so, or should, and locating it correctly determines every subsequent judgement about the argument. Assumption An unstated premise the argument requires in order to work. Identified by negation: negate it and a genuine assumption brings the argument down, while a merely helpful statement leaves it standing. Validity and soundness An argument is valid when the conclusion cannot be false while the premises are true, which is a property of form alone. It is sound when it is valid and the premises are actually true. Affirming the consequent The invalid pattern 'if P then Q; Q; therefore P'. It is the most common deductive distractor because it differs from the valid modus tollens form by only the position of a negation. Base rate How common something is in the population before any test or evidence is applied. Ignoring it makes accurate-sounding tests appear far more informative than they are when the condition is rare. Confounder A third factor associated with both the supposed cause and the outcome, capable of producing the entire observed relationship on its own. Ruled out by randomisation or by an explicit comparison group. Selection effect A difference between groups created by how people entered them rather than by the treatment under study. Optional programmes and voluntary surveys are where it appears most often. Falsifiability The property of a claim that some observation could show it to be wrong. A claim compatible with every possible result carries no information, which is why 'what would change your mind?' is a diagnostic question. Study this next --------------- - Critical thinking skill hub: https://learn.novusstreamsolutions.com/aptitude/skills/critical-thinking - Practise the critical thinking bank: https://learn.novusstreamsolutions.com/cognitive-skills/critical-thinking - Verbal reasoning lesson: https://learn.novusstreamsolutions.com/aptitude/skills/verbal-reasoning/lesson - Government audit suite: https://learn.novusstreamsolutions.com/aptitude/tests/government-audit - Investigator and detective reasoning suite: https://learn.novusstreamsolutions.com/aptitude/tests/investigator-and-detective-reasoning - Critical thinking lesson on Novus Learn: https://learn.novusstreamsolutions.com/aptitude/skills/critical-thinking/lesson Where this material comes from ------------------------------ - Worked items written for Novus Learn. The arguments, survey figures, defect-test numbers and evaluation options above are original and invented for this lesson; no published or copyrighted test item is reproduced. - The five task types named in the summary - inference, assumption, deduction, interpretation, evaluation of arguments - describe a structure used publicly across several critical-thinking assessments; no affiliation with any publisher is claimed or implied. - Terminology follows standard, widely published usage in introductory logic and research methods - validity, soundness, affirming the consequent, base rate, confounder, selection effect. - Novus Learn aptitude construct registry (catalog seed) for the construct scope and the suite mapping shown in the related links. - Public educational framing only - not affiliated with any official exam board, publisher or employer. ! Educational preparation only. Novus Learn does not administer official exams and does not guarantee scores or hiring outcomes. Recommended preparation ======================= - Practice safety judgement: https://learn.novusstreamsolutions.com/aptitude/skills/safety-judgement/lesson - Practice situational judgement: https://learn.novusstreamsolutions.com/aptitude/skills/situational-judgement/lesson - Practice numerical reasoning: https://learn.novusstreamsolutions.com/aptitude/skills/numerical-reasoning/lesson Answer keys, scoring and privacy ================================ ! Answer keys and scoring logic stay server-side and are never included in any download or export. Formal suite answer keys and scoring logic stay on the server and are not part of any download, in any format. Downloadable keys exist only for the open, untimed practice material (the practice packs on the puzzles, cognitive-skills and reasoning practice lab pages), where the answers are already public teaching content. Novus Learn needs no account. 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