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:
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:
(d)