A sample of 28 elements is selected to estimate a 95% confidence interval for the variance of the population. The chi-square values to be used for this interval estimation are
A) 11.808 and 49.645.
B) 14.573 and 43.195.
C) 16.151 and 40.113.
D) 15.308 and 44.461.

Question

A sample of 28 elements is selected to estimate a 95% confidence interval for the variance of the population. The chi-square values to be used for this interval estimation are​
A) 11.808 and 49.645.
B) ​14.573 and 43.195.
C) ​16.151 and 40.113.
D) ​15.308 and 44.461.

Quizplus · Accepted Answer

For a 95% confidence interval for the variance, the chi-square values are determined by the degrees of freedom (n-1) where n is the sample size. For a sample size of 28, the degrees of freedom is 27. The chi-square values for 27 degrees of freedom at the 2.5th and 97.5th percentiles (since it's a two-tailed test for a 95% confidence interval) are approximately 14.573 and 43.195, respectively.

A Sample of 28 Elements Is Selected to Estimate a 95