Step 1 :We are given that the sample mean (\(\bar{x}\)) is $31, the sample standard deviation (s) is $14, and the sample size (n) is 14. We want to construct a confidence interval at a 99% confidence level.
Step 2 :The formula for a confidence interval for a population mean when the population standard deviation is unknown is \(\bar{x} \pm t \frac{s}{\sqrt{n}}\), where t is the t-score corresponding to the desired confidence level and degrees of freedom (which is n - 1).
Step 3 :We need to find the t-score for a 99% confidence level and 13 degrees of freedom. Using a t-distribution table or a calculator, we find that the t-score is approximately 3.012.
Step 4 :Substituting the given values into the formula, we get \(31 \pm 3.012 \frac{14}{\sqrt{14}}\).
Step 5 :Solving this expression, we find that the margin of error is approximately 11.27.
Step 6 :Subtracting and adding this margin of error from the sample mean, we find that the 99% confidence interval for the population mean is \(\boxed{(\$19.7, \$42.3)}\).