In Chapter 8 we examined confidence intervals. Recall that to construct a confidence interval for the mean when the population standard deviation is unknown, the population must follow the normal probability distribution.

To test this condition, the following data show a random sample of weekly visits by patients to Dr. Gregg’s chiropractic office. The data can also be found in the Excel file Dr. Gregg’s office.xlsx.

110 117 78 114 131 67 105 105 93 118 114 93 91 96 109 114 127 116 112 82 92 100 98 67 100 129 107 105 72 65 131 78 103 81

a. Using a = 0.05, perform a chi-square test to determine if the number of patient visits per week follows the normal probability distribution. Note that x = 100.6 and s = 18.7.

b. Determine the p-value using Excel and interpret its meaning.

AppendixLO1