Exercise 1129 Algorithmic A sample of 9 days over the past s

{Exercise 11.29 (Algorithmic)}

A sample of 9 days over the past six months showed that a dentist treated the following numbers of patients: 22, 24, 21, 19, 14, 21, 25, 18, and 27. If the number of patients seen per day is normally distributed, would an analysis of these sample data reject the hypothesis that the variance in the number of patients seen per day is equal to 10? Use a .10 level of significance.

State the null and alternative hypotheses.

0: 2   _________________   
a: 2   _________________   

Calculate the value of the test statistic (to 2 decimals).
______   

The p-value is _________________   

What is your conclusion?
_________________

Solution

Ho: o^2=10
Ha: o^2 not equal to 10
The test statistic is
Chisquare =(n-1)*s^2/o^2
=8*15.444/10
= 12.35
Given a=0.1, the critical value of chisquare with 0.9, df=n-1=8 is 13.36 (from chisquare table)
Since 12.35 is less than 13.36, we do not reject Ho.
So we can conclude that the variance in the number of patients seen per day equal to 10