P1: Uncertainty
22 free practice questions on uncertainty, Section D of the CIMA Management Accounting (P1) question bank. Topics include Expected value, Sensitivity analysis, Minimax regret, Decision tree, Simulation, Risk vs uncertainty. Each question carries its syllabus reference and a worked explanation. Practise them in the quiz with instant feedback, or read every question with its answer further down this page.
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All 22 uncertainty questions
The same questions the quiz above draws on, in syllabus order, each with its answer and worked explanation. 14 are multiple choice and 8 are numerical, where you work the answer out before choosing it.
A project has three possible outcomes: a £80,000 profit (probability 0.4), a £40,000 profit (probability 0.4), and a £10,000 loss (probability 0.2). What is the expected value of the project?
- £36,667
- £46,000
- £44,000
- £48,000
Show answer and explanation
Answer: B. Expected value = Σ(probability × outcome) = (0.4 × £80,000) + (0.4 × £40,000) + (0.2 × −£10,000) = £32,000 + £16,000 − £2,000 = £46,000. £48,000 leaves out the loss outcome altogether (£32,000 + £16,000), and £44,000 deducts the expected loss twice. The £36,667 figure is the simple (unweighted) average of the three outcomes, ignoring the probabilities. Expected value is a long-run average, not a guaranteed outcome, and can mask significant downside risk.
In decision theory, the key difference between risk and uncertainty is that:
- Risk is always considered a bad thing, while uncertainty may turn out to be either good or bad
- Risk only applies to purely financial decisions; uncertainty applies to all other decisions
- Under risk, probabilities of each outcome can be estimated; under uncertainty, they cannot meaningfully be assigned
- Under uncertainty specifically, the decision maker can insure against every single possible loss
Show answer and explanation
Answer: C. Risk describes situations where the possible outcomes are known and probabilities can be assigned to them (enabling tools such as expected value and decision trees). Uncertainty describes situations where the range of outcomes or their probabilities cannot meaningfully be determined — often in novel or unprecedented situations. Both risk and uncertainty can lead to positive or negative outcomes. Insurance transfers financial risk but cannot eliminate uncertainty. The distinction determines which analytical tools are appropriate.
A decision maker using the maximin criterion will choose the option that:
- Maximises the best possible outcome across all options
- Maximises the expected value across all probability-weighted outcomes
- Minimises the maximum possible regret from any given decision
- Maximises the worst possible outcome — the option whose minimum payoff is highest
Show answer and explanation
Answer: D. Maximin is a conservative, pessimistic decision rule: the decision maker assumes the worst will happen for each option and then chooses the option whose worst case (minimum payoff) is the highest. It is used under conditions of uncertainty where probabilities cannot be assigned. Maximising the best possible outcome is the maximax rule (optimistic). Minimising maximum regret is the minimax regret rule. Maximising expected value requires probabilities to be assigned and is used under risk, not pure uncertainty.
Sensitivity analysis in the context of short-term decisions is used to:
- Determine how much a key variable (price or volume) must change before the decision changes
- Assign costs to products using multiple different cost drivers instead of one
- Calculate the exact probability that a project will be profitable
- Replace the need for budgets by analysing historical data only
Show answer and explanation
Answer: A. Sensitivity analysis asks how robust a decision is by calculating how much a critical variable — such as selling price, volume, variable cost or fixed cost — would need to change (relative to its expected value) before the preferred option would no longer be optimal. The variable with the smallest percentage change required is the most sensitive and deserves the most management attention. It does not assign probabilities, handle cost drivers, or replace budgets — it is a 'what-if' technique used alongside the main analysis.
A decision maker using the maximax criterion will select the option with the:
- Highest minimum payoff
- Lowest maximum possible loss
- Lowest variance in possible outcomes
- Highest maximum possible payoff
Show answer and explanation
Answer: D. Maximax is an optimistic decision rule: the decision maker focuses only on the best possible outcome of each option and chooses the one with the highest maximum payoff, ignoring the risk of poor outcomes. It is the opposite of maximin (which focuses on the worst case). A maximax decision maker is effectively risk-seeking. Choosing the highest minimum payoff is maximin; minimising the maximum loss is minimax; lowest variance is associated with risk-averse behaviour under uncertainty.
The minimax regret criterion selects the option that:
- Minimises the maximum possible regret — the opportunity cost of not choosing the best option in each state
- Maximises the expected payoff across all states of the world
- Minimises the overall total cost of the decision across every possible outcome
- Maximises the minimum guaranteed payoff regardless of which state of the world occurs
Show answer and explanation
Answer: A. Minimax regret calculates the regret (the difference between the best possible payoff in each state of the world and the payoff actually achieved under each option) and selects the option whose maximum regret is smallest. It is a compromise between the pessimism of maximin and the optimism of maximax. Maximising expected payoff requires probabilities and is used under risk. Minimising overall cost may not be the same as minimising maximum regret. Maximising minimum guaranteed payoff is maximin.
In a decision tree, what do square nodes (boxes) and circular nodes (circles) represent respectively?
- Squares represent probability nodes where chance decides; circles represent decision nodes where a choice is made
- Squares represent decision points where the decision maker chooses; circles represent chance nodes where probability decides
- Both represent the same type of node — the shape is purely aesthetic
- Squares represent costs incurred; circles represent revenues generated by the decision
Show answer and explanation
Answer: B. In a decision tree, square nodes are decision points — the decision maker chooses between alternative courses of action. Circular nodes are chance (probability) nodes — the outcome is determined by chance, with each branch assigned a probability. The tree is drawn left to right and evaluated by working back from right to left (rolling back), replacing chance nodes with expected values and choosing the decision node branch with the highest expected value. This structure is the standard convention in management accounting and decision analysis.
A decision tree shows: Project X leads to a chance node with outcomes £80,000 (prob 0.6) and £20,000 (prob 0.4). Project Y gives a certain outcome of £55,000. Which project should be chosen, and what is its expected value?
- Project Y; £55,000
- Project Y; £48,000
- Project X; £50,000
- Project X; £56,000
Show answer and explanation
Answer: D. Expected value of Project X = (0.6 × £80,000) + (0.4 × £20,000) = £48,000 + £8,000 = £56,000. Expected value of Project Y = £55,000 (certain). Since £56,000 > £55,000, Project X is preferred on an expected value basis. The rollback method values chance nodes as expected values, then selects the highest value at each decision node. The £50,000 figure misapplies probabilities; a risk-averse decision maker might prefer Project Y despite its lower expected value.
Without additional information, a company chooses Project A with an expected value of £40,000. With perfect information, it would choose the best project in each state: good market (prob 0.6): best outcome £60,000; poor market (prob 0.4): best outcome £27,500. What is the expected value of perfect information (EVPI)?
- £7,000
- £47,000
- £20,000
- £3,000
Show answer and explanation
Answer: A. Expected value with perfect information (EVWPI) = (0.6 × £60,000) + (0.4 × £27,500) = £36,000 + £11,000 = £47,000. EVPI = EVWPI − expected value without information = £47,000 − £40,000 = £7,000. This represents the maximum amount the company should pay for information that perfectly predicts which state of the world will occur. The £47,000 figure is the expected payoff with perfect information, not the value of that information. EVPI is always non-negative; if it is small, acquiring information may not be worth the cost. £20,000 and £3,000 do not follow from the figures.
A project has an NPV of £20,000. The present value of the variable cost cash flows is £100,000. By what percentage would variable costs need to increase before the project becomes unviable?
- 5%
- 20%
- 10%
- 25%
Show answer and explanation
Answer: B. Sensitivity of variable costs = project NPV ÷ PV of the variable being tested = £20,000 ÷ £100,000 = 20%. If variable costs were 20% higher, the negative impact on NPV would be £100,000 × 20% = £20,000, exactly eliminating the positive NPV. This is the percentage change that renders the project marginal. A variable with a low sensitivity percentage is the most critical because a small adverse change makes the project unviable. The 5% and 10% figures understate the sensitivity. 25% divides the NPV by £80,000 instead of £100,000.
Simulation models (such as Monte Carlo simulation) are used in decision making under uncertainty because they:
- Guarantee the correct answer by testing every single possible combination exhaustively
- Eliminate all risk from the decision entirely, regardless of the variables involved
- Model the simultaneous effect of uncertainty across multiple variables, producing a probability distribution of outcomes
- Apply only where exact probability distributions are unknown for all variables
Show answer and explanation
Answer: C. Simulation — particularly Monte Carlo simulation — models the combined effect of uncertainty in multiple variables simultaneously, generating thousands of random scenarios and producing a probability distribution of outcomes (such as profit or NPV). This gives decision makers a richer picture of risk than single-variable sensitivity analysis. Simulation does not guarantee the correct answer (it provides a probability distribution, not certainty), does not eliminate risk, and can be used with assumed or empirically estimated distributions for each variable.
A manager must choose between three options. The possible payoffs (£000) are: Option 1: good (£80), average (£40), poor (£10). Option 2: good (£60), average (£50), poor (£30). Option 3: good (£90), average (£20), poor (−£5). Which option does the maximin rule select?
- Option 1
- Option 2
- Option 3
- All options are equivalent under maximin
Show answer and explanation
Answer: B. Maximin identifies the minimum payoff for each option and selects the highest: Option 1 minimum = £10,000; Option 2 minimum = £30,000; Option 3 minimum = −£5,000 (a loss). The highest minimum payoff is Option 2 (£30,000), so maximin selects Option 2. This is a pessimistic, risk-averse rule that protects against the worst outcome. A risk-seeking maximax rule would choose Option 3 (highest maximum of £90,000), and an expected value approach would require probabilities.
Using the same options as above: Option 1: good £80, poor £10. Option 2: good £60, poor £30. Option 3: good £90, poor −£5. Which option does the minimax regret rule select?
- Option 3
- Option 2
- Option 1
- Option 1 and Option 2 are equally preferred
Show answer and explanation
Answer: C. Regret table: In a good state (best = £90): Option 1 regret = 90−80 = £10; Option 2 regret = 90−60 = £30; Option 3 regret = 0. In a poor state (best = £30): Option 1 regret = 30−10 = £20; Option 2 regret = 0; Option 3 regret = 30−(−5) = £35. Maximum regret: Option 1 = max(10,20) = £20; Option 2 = max(30,0) = £30; Option 3 = max(0,35) = £35. Minimax regret selects the option with the lowest maximum regret: Option 1 (£20,000). Option 2 has maximum regret £30,000 (in good state) and Option 3 has £35,000 (in poor state). Option 1 is preferred by minimax regret. Note: a risk-seeking maximax approach would choose Option 3; maximin would choose Option 2 (highest minimum of £30,000).
When comparing two investment projects with the same expected return, the project with the higher standard deviation of returns would be regarded as:
- Preferred, because higher standard deviation means higher expected return
- Less risky, because its outcomes are more predictable
- Equivalent in risk to the lower standard-deviation project
- Riskier, because its returns are more widely dispersed around the expected value
Show answer and explanation
Answer: D. Standard deviation measures the spread of possible outcomes around the expected value; a higher standard deviation means greater variability and therefore greater risk. When expected returns are equal, a risk-averse decision maker would prefer the project with the lower standard deviation. Higher standard deviation does not imply higher expected return (they are compared here on the same expected return), and it implies greater, not lesser, unpredictability. In this case the coefficient of variation (standard deviation ÷ expected return) gives the same ranking because expected returns are equal.
A company must choose between two strategies. Strategy A: EV = £45,000. Strategy B: profit if market is good (prob 0.7) = £70,000; loss if market is poor (prob 0.3) = £20,000. Which strategy should be chosen and what is Strategy B's expected value?
- Strategy A; Strategy B EV = £55,000
- Strategy A; Strategy B EV = £43,000
- Strategy B; Strategy B EV = £55,000
- Strategy B; Strategy B EV = £43,000
Show answer and explanation
Answer: B. Strategy B EV = (0.7 × £70,000) + (0.3 × −£20,000) = £49,000 − £6,000 = £43,000. Since Strategy A EV (£45,000) > Strategy B EV (£43,000), Strategy A should be chosen on an expected value basis. The £55,000 figures arise from adding probabilities instead of computing expected values (0.7 × £70,000 + 0.3 × £20,000 = £49,000 + £6,000 = £55,000 — treating the loss as a gain). Expected value calculation must correctly account for the sign of each payoff.
A risk-averse decision maker, when faced with two options of equal expected value, will typically:
- Choose the option with the higher variance of possible outcomes
- Be indifferent between the two options
- Choose the option with the lower variance (less risky) of possible outcomes
- Always choose the option with the highest possible payoff
Show answer and explanation
Answer: C. A risk-averse decision maker dislikes uncertainty and, all else equal, prefers the option with more predictable outcomes — lower variance, standard deviation or spread of possible results — even at the same expected return. Risk-seeking behaviour involves preferring more variance (maximax thinking). Risk-neutral decision makers base decisions purely on expected values and are genuinely indifferent when expected values are equal. Always choosing the highest payoff is maximax, which is risk-seeking, not risk-averse.
A project is most sensitive to changes in which variable?
- The variable whose absolute pound value happens to be highest overall
- The variable for which the sensitivity percentage is highest
- The variable that management finds easiest to control operationally
- The variable with the lowest sensitivity percentage, where a small change makes the project unviable
Show answer and explanation
Answer: D. The sensitivity percentage for a variable is the percentage change required in that variable before the NPV falls to zero. The variable with the lowest sensitivity percentage requires the smallest adverse change to destroy the project's viability — it is therefore the most sensitive and most critical. A low sensitivity percentage means little room for error. The highest sensitivity percentage means the project can withstand a large change before failing. Neither absolute value nor management control determines sensitivity.
In Monte Carlo simulation, each 'run' of the model involves:
- Randomly selecting a value for each uncertain variable from its distribution and calculating the outcome
- Using the most likely value for every variable simultaneously
- Using only the best-case values for every uncertain variable simultaneously
- Calculating the expected value of each variable and using those to compute the outcome
Show answer and explanation
Answer: A. Each Monte Carlo run randomly samples a value for each uncertain variable from its assumed probability distribution — for example, picking a selling price from a uniform or normal distribution — then calculates the model output (such as NPV) for that combination of values. After thousands of runs, the results form a probability distribution of the output, showing the range of outcomes and their relative likelihoods. Using the most likely value, best-case values or expected values would all give a single deterministic result rather than the distribution that Monte Carlo generates.
A limitation of using expected value as the sole basis for decisions under risk is that:
- It is impossible to calculate without perfect probability data
- It always leads to the correct decision being made in every situation
- It represents an average outcome that may never occur, and ignores the variability (risk) of outcomes
- It is too conservative and always leads to rejection of profitable projects
Show answer and explanation
Answer: C. The expected value is a probability-weighted average; the actual outcome will be one of the specific scenarios (not the weighted average), which may differ substantially from the EV. Two projects with the same EV may have very different risk profiles — one with a narrow range of outcomes, another with a wide range including large losses. EV also assumes the decision is repeated many times, which may not be true for a one-off decision. Probabilities can be estimated even without certainty, EV does not guarantee correctness, and it is not inherently conservative.
A two-way (or multi-variable) sensitivity analysis is more informative than single-variable sensitivity because it:
- Calculates the exact probability of each individual outcome occurring
- Produces a single definitive answer, unlike single-variable analysis
- Eliminates the need to estimate probabilities for each individual variable
- Shows how the outcome changes as two or more variables move together, reflecting real-world conditions
Show answer and explanation
Answer: D. Single-variable sensitivity varies one input at a time while holding all others constant — useful but unrealistic, since in practice multiple variables change together. Two-way analysis shows, for example, how NPV changes as both selling price and volume vary, producing a matrix of results that reflects the combined effect. It does not calculate probabilities (that is simulation), does not eliminate uncertainty, and produces a range of results rather than a single answer. It gives a richer picture than single-variable analysis and helps identify critical combinations of conditions.
The expected value of imperfect information (EVII) is:
- Less than or equal to EVPI, because imperfect information cannot provide certainty
- Always greater than EVPI, because imperfect information covers more scenarios
- Always equal to the expected value of perfect information (EVPI)
- Always negative, because acquiring information is costly
Show answer and explanation
Answer: A. Imperfect information (such as market research) tells the decision maker something about the likely state of the world but does not guarantee accuracy — there is still a chance of incorrect signals. Perfect information would always indicate the correct state. Therefore, the improvement in decision making (and expected payoff) from imperfect information is less than from perfect information, making EVII ≤ EVPI. EVII is the maximum worth paying for imperfect information and is always non-negative (you cannot be worse off by having more information if you can choose to ignore it).
Project A has an expected return of £200,000 and a standard deviation of £50,000. Project B has an expected return of £300,000 and a standard deviation of £60,000. Which project is relatively more risky?
- Project A, because its standard deviation (£50,000) is lower
- Project A, because its coefficient of variation (25%) is higher than Project B's (20%)
- Project B, because its standard deviation (£60,000) is higher
- Project B, because its expected return (£300,000) is higher
Show answer and explanation
Answer: B. The coefficient of variation (CV) = standard deviation ÷ expected return expresses risk relative to return, allowing fair comparison when returns differ. Project A: CV = £50,000 ÷ £200,000 = 25%. Project B: CV = £60,000 ÷ £300,000 = 20%. Project A is relatively more risky (higher CV), despite having the lower absolute standard deviation. Comparing standard deviations alone (£50,000 vs £60,000) is misleading when expected returns differ significantly. A risk-averse investor comparing equal-return projects uses standard deviation; comparing different-return projects should use the coefficient of variation.
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