# An SRS of 380 high school seniors gained an average of ?¯=21.02 points in their second attempt at the SAT Mathematics exam. Assume that the change in score has a Normal distribution with standard deviation ?=49.89. We want to estimate the mean change in score ? in the population of all high school seniors. (a) Using the 68 – 95 – 99.7 Rule or the ?-table (Table A), give a 95% confidence interval (?,?) for ? based on this sample. ? :     ? :

Question
An SRS of 380 high school seniors gained an average of ?¯=21.02 points in their second attempt at the SAT Mathematics exam. Assume that the change in score has a Normal distribution with standard deviation ?=49.89. We want to estimate the mean change in score ? in the population of all high school seniors.

(a) Using the 68 – 95 – 99.7 Rule or the ?-table (Table A), give a 95% confidence interval (?,?) for ? based on this sample.

? :

? :