A random sample of 25 workers showed that the average workweek in the United States is...

A random sample of 25 workers showed that the average workweek in the United States is down to only 35 hours, largely because of a rise in part-time workers. The variance of the sample was 18.49 hours. Assuming that the population is normally distributed, calculate a 98% confidence interval for the population standard deviation.

Expert Solution

Solution :

Given that,

s² = 18.49

²_L = ²_/2,df = 42.980

²_R = ²_{1 -} _/2,df = 10.856

The 98% confidence interval for is,

(n - 1)s² / ²_/2 < < (n - 1)s² / ²_{1 -} _/2

24 * 18.49 / 42.980 < < 24 * 18.49 / 10.856

3.21 < < 6.39

(3.21 , 6.39)

orchestra answered 2 years ago

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