Question

To estimate the average annual expenses of students on books and class materials a sample of size 36 is taken. the sample mean is $850 and the sample standard deviation is $54. a 99 percent confidence interval for the population mean is

Answer 1

The 99 percent confidence interval for the population mean is found from:
$\bar{x}-2.576\frac{s}{ \sqrt{n} }\ \textless \ \mu\ \textless \ \bar{x}+2.576\frac{s}{ \sqrt{n} }$
$850-2.576\frac{54}{ \sqrt{36} }\ \textless \ \mu\ \textless \ 850+2.576\frac{54}{ \sqrt{36} }$
The answer is:
$826.82\ \textless \ \mu\ \textless \ 873.18$