Chapter 3.2, Problem 45BB

a.

To determine

To find: The variance ${\sigma }^2$ of the population $\left\{9\text{cigarettes,}10\text{cigarettes,}20\text{cigarettes}\right\}$.

b.

To determine

To find: The sample variance $s^2$ and then find the mean of the nine sample variances $s^2$.

c.

To determine

To find: The population variance ${\sigma }^2$ and then find the mean of the nine population variances ${\sigma }^2$.

d.

To determine

To identify: Which of the results in values are better estimates of ${\sigma }^2$.

e.

To determine

To check: Whether the s is an unbiased estimator of $\sigma$ or not.