Decision Making Flashcards

A bar chart shows monthly sales. January: 200, February: 250, March: 300, April: 280. What was the mean monthly sales over these four months?

Answer: 257.5

Mean = (200 + 250 + 300 + 280) / 4 = 1030 / 4 = 257.5.

P, Q, R, S complete tasks in order. If P fails, Q takes over. If both fail, R takes over. Only S always succeeds. P has a 0.2 failure rate. What is the probability P completes the task?

Answer: 0.8

P succeeds with probability 1 − 0.2 = 0.8. The question asks only about P completing it, not the overall system.

A graph shows a negative correlation between hours of exercise and resting heart rate. This means:

Answer: People who exercise more tend to have lower resting heart rates

Negative correlation means as one variable increases, the other tends to decrease. This describes an association, not causation.

A puzzle: 5 people each shake hands with every other person exactly once. How many handshakes occur?

Answer: 10

C(5,2) = 10. Each unique pair shakes hands once.

'All prescribed medications have side effects. Aspirin has side effects.' Does this prove aspirin is prescribed?

Answer: No — having side effects does not prove it is prescribed, as non-prescribed drugs can also have side effects

The first statement gives a property of all prescribed medications, but does not say only prescribed medications have side effects. Therefore side effects do not prove prescription status.

A table shows: Drug A cures 80% of cases in trial 1 (20 patients) and 40% in trial 2 (100 patients). What is the overall cure rate?

Answer: 50%

Total cured = (0.8×20) + (0.4×100) = 16 + 40 = 56. Total patients = 120. Rate = 56/120 ≈ 46.7% ≈ 50%. Weighted: 56/120 = 46.7%. Closest answer is 50%. (Note: exact = 46.7%; 50% is the nearest option.)