26. The superintendent of a large school district, having once had a course in probability and statistics, 23 pˆ

believes that the number of teachers absent on any given day has a Poisson distribution with parameter l. Use the accompanying data on absences for 50 days to derive a large-sample CI for l. (Hint:

The mean and variance of a Poisson variable both equal l, so has approximately a standard normal distribution.

Now proceed as in the derivation of the interval for p by making a probability statement [with probability 1  a] and solving the resulting inequalities for l [see the argument just after (8.10)].

Number of absences 0 1 2 3 4 5 6 7 8 9 10 Frequency 1 4 8 10 8 7 5 3 2 1 1