A2 June 2023 Q2
2. An outdoor theatre is holding a summer gala performance. The theatre owner must decide whether to take out insurance against rain for this performance.
The theatre owner estimates that
- on a fine day, the total profit will be £15 000
- on a wet day, the total loss will be £20 000
Insurance against rain costs £2 000. If the performance must be cancelled due to rain, then the theatre owner will receive £16 000 from the insurer. If the performance is not cancelled due to rain, then the theatre owner will receive nothing from the insurer.
The probability of rain on the day of the gala performance is 0.2
Draw a decision tree and hence determine whether the theatre owner should take out the insurance against rain for this performance. (5)
| Scheme | Marks | AO |
|---|---|---|
![]() | M1 A1 A1 M1 | 3.3 1.1b 3.4 3.4 |
| The theatre owner should take out the insurance | A1 | 1.1b |
| (5) | ||
| (5 marks) |
Notes
M1: tree diagram with at least four end pay-offs, one decision node and two chance nodes used correctly (may not have all shapes drawn e.g. no triangles on end pay-offs)
A1: correct structure of tree diagram with each arc labelled correctly with word and associated probabilities (condone incorrect shapes for decision and chance nodes)
A1: at least three end pay-offs correct including triangles; all four attempted (not dependent on previous A mark so M1 A0 A1 is possible)
M1: both chance nodes completed with at least one value correct. Must be filled in on their diagram.
A1: cao for chance and decision nodes (all three correctly filled in on diagram) + clear conclusion ‘insure’ including double line through the inferior option.
