For a sample of size 18, the critical values of chi-square for a 99 percent confidence interval for the population variance are: A)6.262, 27.49 B)5.697, 35.72 C)5.629, 26.12 D)7.261, 25.00 d.f. = n - 1 = 17, we get χ²_L = 5.697 and χ²_U = 35.72 from AppendixE.

Question

Quizplus · Accepted Answer

According to the given information, we need to find the critical values of chi-square for a 99% confidence interval for the population variance with a sample size of 18. The degrees of freedom for this case would be n-1 = 18-1 = 17.

Using Appendix E, we can find the critical values for the chi-square distribution at 0.005 and 0.995 probability levels with 17 degrees of freedom. These values are 5.697 and 35.72 respectively. Therefore, the critical values of chi-square for a 99% confidence interval for the population variance are between 5.697 and 35.72.

The correct choice is B.

For a Sample of Size 18, the Critical Values of Chi-Square