The class mean score on a test was 60, and the standard deviation was 15. If Jack's score was within...

1. Translate the problem requirements: "Within 2 standard deviations of the mean" means Jack's score falls between \(\mathrm{mean} - 2 \times \mathrm{standard\ deviation}\) and \(\mathrm{mean} + 2 \times \mathrm{standard\ deviation}\). We want the lowest possible score in this range.
2. Identify the acceptable score range: Calculate the bounds: lower = \(60 - 2 \times 15 = 30\), upper = \(60 + 2 \times 15 = 90\).
3. Determine the minimum score: The lowest score in [30, 90] is 30.

Final Answer

The lowest score Jack could have received while still within 2 standard deviations of the mean is 30 (choice A).