An auditor, examining a total of 830

accounts receivable of a corporation, took a random sample of 80

of them. The sample mean was $126.94,

and the sample standard deviation was $43.22

Complete parts a through e.

a. Using an unbiased estimation procedure, find an estimate of the population mean.

An estimate of the population mean is $_____ .

(Round to the nearest cent as needed.)

b. Using an unbiased estimation procedure, find an estimate of the variance of the sample mean.

An estimate of the variance of the sample mean is _____ .

(Round to three decimal places as needed.)

c. Find a 90% confidence interval for the population mean.

$ _____ < <$ _____

(Round to the nearest cent as needed.)

d. A statistician found, for the population mean, a confidence interval running from $116.94

to $136.94.

What is the probability content of this interval?

The probability content is _____ .

(Round to four decimal places as needed.)

e. Find a 95% confidence interval for the total amount of these 830

accounts.

$ _____

(Round to the nearest dollar as needed.)