The number of times a Web server is accessed per minute is known to follow a Poisson distribution. A random sample of size 8, each over a minute, shows the number of times that the server is accessed as follows: 5, 3, 2, 0, 6, 1, 1, 2.
Find a 90% confidence interval for the mean number of times that the Web server is accessed per minute.
Can we conclude that the mean number of times that the server is accessed per minute is different from 4 at the 10% level of significance?