Chapter 8.1, Problem 13E

a.

To determine

To interpret: The confidence interval.

Explanation of Solution

Given:

The confidence interval is $51,492\pm 431=\left(51061,51923\right)$

The confidence interval states that there is 90% certainty that median household income in Arizona would fall between $51061 and $51923.

c.

To determine

To explain: The term confidence level.

Explanation of Solution

Confidence level provides the probability of the values that are expected to capture the population parameter. The confidence level is used to calculate the value of the level of significance $\left(\alpha \right)$ .

Here, the probability to capture the median household income is 90%