pts The distribution of blood cholesterol levels (in mg/dl) among 14-year-old boys can be well approximated with the N( 170, 30) distribution. For random samples of 25 boys, what are the properties of the sampling distribution of average cholesterol levels in such samples? [Select] Based on the 68-95-97.5% rule, what is approximately the range of average cholesterol levels in random samples of 25 boys representing the middle 99.7% of possible values? [Select]