Step 1 :Calculate the test statistic using the formula \(t = \frac{M - \mu}{SD / \sqrt{n}}\). Substitute the given values into the formula: \(t = \frac{58.6 - 60.4}{17.2 / \sqrt{61}}\).
Step 2 :Simplify the calculation to get \(t = \frac{-1.8}{17.2 / 7.81}\).
Step 3 :Further simplify the calculation to get \(t = \frac{-1.8}{2.20}\).
Step 4 :Calculate the final value of the test statistic to get \(t = -0.818\).
Step 5 :Calculate the p-value, which is the probability of observing a test statistic as extreme as -0.818, assuming the null hypothesis is true. Since this is a two-tailed test, we need to find the probability of observing a test statistic as extreme as -0.818 in either tail of the distribution. Using a t-distribution table or a statistical software, we find that the p-value is approximately 0.4164.
Step 6 :Compare the p-value to the significance level. The p-value (0.4164) is greater than the significance level (0.001).
Step 7 :Since the p-value is greater than the significance level, we fail to reject the null hypothesis.
Step 8 :There is not sufficient evidence to warrant rejection of the claim that the population mean is not equal to 60.4. Therefore, \(\boxed{\text{We fail to reject the null hypothesis}}\).