The grade point averages for 11 randomly selected students are listed below. Assume the data are...

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

Solutions

Expert Solution

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 )

orchestra answered 1 year ago

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