Final answer:
Without specific daily probability mass functions, an exact probability cannot be given, but if accidents are equally likely every day, the chance of more accidents on Friday than Thursday would be 0.5 because of the binary outcome and assuming independence.
Step-by-step explanation:
The probability that more accidents occur on Friday than on Thursday when the number of accidents follows a Poisson distribution at an average of three per week can be calculated using the properties of the Poisson distribution. However, without specific probability mass functions for each day, we cannot determine the exact probability. Generally, if accidents are equally likely to happen on any day and follow the same probability mass function, the probability of more accidents on Friday compared to Thursday is 0.5, since there are only two outcomes: more accidents or fewer/equal accidents, assuming independence of occurrences on both days.
For a more accurate assessment, you would need the probability mass function for the number of accidents on Thursday and Friday. With those, you could sum the probabilities of all scenarios where Friday's accidents outnumber Thursday's.
Example: If the PMF for Thursday and Friday are the same and represent a Poisson distribution with a mean (μ) of three accidents per week, then you could sum the probabilities from P(Friday > Thursday) using iterative methods.