5. The maintenance department of a college receives requests for replacement light bulbs at a rate of 2 per week.
Find the probability that in a randomly chosen week the number of requests for replacement light bulbs is
- exactly 4,
- more than 5 .
Three weeks before the end of term the maintenance department discovers that there are only 5 light bulbs left.
- Find the probability that the department can meet all requests for replacement light bulbs before the end of term.
The following term the principal of the college announces a package of new measures to reduce the amount of damage to college property. In the first 4 weeks following this announcement, 3 requests for replacement light bulbs are received.
- Stating your hypotheses clearly test, at the \(5 \%\) level of significance, whether or not there is evidence that the rate of requests for replacement light bulbs has decreased.
(5)