Question

The number of hours of reserve capacity of

10

randomly selected automotive batteries is shown.

1.72	1.84	1.59	1.62	1.76
1.94	1.31	1.56	1.41	2.08

Assume the sample is taken from a normally distributed population. Construct

95​%

confidence intervals for​ (a) the population variance

sigmaσsquared2

and​ (b) the population standard deviation

sigmaσ.

​(a) The confidence interval for the population variance is left parenthesis nothing comma nothing right parenthesis .,.

​(Round to three decimal places as​ needed.)

Answer 1

From the given sample data : n=10 , ,

The sample standard deviation is ,

The excel function is , =CHIINV(0.975,9)

The excel function is , =CHIINV(0.025,9)

Therefore , the 95​% confidence intervals for​ the population variance is ,