The mean replacement time for a random sample of 12 CD players is 8.6 years with a standard deviation of 5.8 years. Construct the 98% confidence interval for the population variance, σ2. Assume the data are normally distributed, and round to the nearest hundredth when necessary.
A) (14.97, 121.19)
B) (3.87, 11.01)
C) (2.58, 20.89)
D) (14.11, 103.62)

Question

Quizplus · Accepted Answer

The confidence interval for the population variance is calculated using the chi-square distribution. With 11 degrees of freedom (n-1), the 98% confidence interval for the variance is calculated using the chi-square critical values. The correct interval is (14.97, 121.19).

The Mean Replacement Time for a Random Sample of 12