Step 1 :Given values are: population mean (\( \mu \)) = 100, sample mean (\( \bar{x} \)) = 91.7, sample standard deviation (s) = 12.5, and sample size (n) = 30.
Step 2 :Calculate the test statistic using the formula: \( t_{stat} = \frac{\bar{x} - \mu}{s / \sqrt{n}} \).
Step 3 :Substitute the given values into the formula to get: \( t_{stat} = \frac{91.7 - 100}{12.5 / \sqrt{30}} \approx -3.64 \).
Step 4 :Calculate the p-value. Since it's a left-tailed test, we use the cumulative distribution function (cdf) instead of the survival function (sf).
Step 5 :The p-value is approximately 0.00053.
Step 6 :Since the p-value is less than the significance level of 0.05, we reject the null hypothesis.
Step 7 :This means that we have enough evidence to support the claim that the population mean is less than 100.
Step 8 :The final answer is: The test statistic is approximately \(\boxed{-3.64}\) and the p-value is approximately \(\boxed{0.00053}\). We \(\boxed{reject}\) the null hypothesis.