# Question

Referring to Exercise 8.11a, assume that the population standard deviation equals 33. How large a random sample of public owner-controlled companies is needed to make us?

In exercise Suppose that a random sample of 100 public owner- controlled companies in New Zealand is found to give a mean audit delay of 82.6 days, and assume that the population standard deviation equals 33 days. Calculate a 95 percent confidence interval for the population mean audit delay for all public owner-controlled companies in New Zealand.

a. 95 percent confident that the sample mean audit delay is within a margin of error of four days of m, the population mean audit delay?

b. 99 percent confident that is within a margin of error of four days of μ?

In exercise Suppose that a random sample of 100 public owner- controlled companies in New Zealand is found to give a mean audit delay of 82.6 days, and assume that the population standard deviation equals 33 days. Calculate a 95 percent confidence interval for the population mean audit delay for all public owner-controlled companies in New Zealand.

a. 95 percent confident that the sample mean audit delay is within a margin of error of four days of m, the population mean audit delay?

b. 99 percent confident that is within a margin of error of four days of μ?

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