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 group of answer choices $823.72 to $876.28 $832.36 to $867.64 $826.82 to $873.18 $825.48 to $874.52