We want to estimate the mean change in score in the population of all high school seniors.

μ

 points in their second attempt at the SAT Mathematics exam. Assume that the change in score has a Normal distribution with standard deviation 51.654.

Find σx, the standard deviation of the mean change of x (bar). ___(±0.001).

Using the 68-95-99.7 Rule (Empirical Rule), give a 95% confidence interval for μ based on this sample.

Confidence interval (±0.001) is between ____ and____