In: Statistics and Probability
The grade point averages for 11 randomly selected students are listed below. Assume the data are normally distributed.
2.0 3.2 1.8 2.9 0.9 4.0 3.3 2.9 3.6 0.8 2.7
Construct a 99% confidence interval for the population standard deviation
From sample data,
= 2.55 , S = 1.0539
chi-square critical value at 0.01 significance level with 10 df = 2.156 , 25.188
99% confidence interval for is
Sqrt [ ( n - 1) S2 / U ] < < Sqrt [ ( n - 1) S2 / L]
sqrt [ 10 * 1.05392 / 25.188 ] < < sqrt [ 10 * 1.05392 / 2.156 ]
0.664 < < 2.211
99% CI is ( 0.664 , 2.211 )