Chapter B.2, Problem 9AYU

a.

To determine

To construct: A 90% confidence interval for ${\sigma }^2$ if the sample size is $n\text{=}20$.

b.

To determine

To construct: A 90% confidence interval for ${\sigma }^2$ if the sample size is $n\text{=}30$.

To find: The effect on width of confidence interval when the sample size is increased.

c.

To determine

To construct: A 98% confidence interval for ${\sigma }^2$ if the sample size is $n\text{=}20$.

To compare: The result with part (a).

To find: The effect on width of confidence interval by increasing level of significance.