Given:
Number (n) of adults sampled = 2816
mean = 14.7
standard deviation (s) = 10.4
The interval estimate using a confidence coefficient of 0.95
The interval estimate can be calculated using the formula:
![\text{Interval estimate = mean }\pm z(\frac{s}{\sqrt[]{n}})^{}](https://img.qammunity.org/2023/formulas/mathematics/college/xquoz23plvgl090tw2mt9wj9kknwsxwbju.png)
where:
z is the z-score for the given confidence interval
From the z-score/confidence coefficient table, the z-score for a confidence coefficient of 0.95 is 1.96
The table is shown below:
When we substitute into the formula, we have:
![\begin{gathered} \text{Interval estimate = 14.7 - 1.96(}\frac{10.4}{\sqrt[]{2816}})\text{ to 14.7 + 1.96(}\frac{10.4}{\sqrt[]{2816}}) \\ =\text{ }14.7\text{ - 0.38413 to 14.7 + 0.38}413 \\ \approx\text{ 14.32 to 15.08} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/p2dume2s4bqr35qpspmbjg91fl7vn8uzgq.png)
(d)