ELEMENTARY STATISTICS
posted by DARLENE on .
50 MATH PROFESSORS WERE ASKED HOW LONG IT TAKES TO GRADE A STUDENT'S HOMEWORK ASSIGNMENT. THE MEAN GRADING TIME FOR THE SAMPLE WAS 36.2 MINUTES WITH A STANDARD DEVIATION OF 4.8 MINUTES. WHAT IS THE 99% CONFIDENCE INTERVAL FOR THE MEAN GRADING TIME OF ALL MATH PROFESSORS?

50 MATH PROFESSORS WERE ASKED HOW LONG IT TAKES TO GRADE A STUDENT'S HOMEWORK ASSIGNMENT. THE MEAN GRADING TIME FOR THE SAMPLE WAS36.2 MINUTES WITH A STANDARD DEVIATION OF 4.8 MINUTES. WHAT IS THE 82% CONFIDENCE INTERVAL FOR THE MEAN GRADING TIME OF ALL MATH PROFESSORS?

First, please do not use all capitals. Online it is like SHOUTING. Not only is it rude, but it is harder to understand. Thank you.
99% = mean ± 1.645 SD, .005 of scores are beyond at each end.
82% = mean ± 1.342 SD, .09 of scores are beyond at each end.
These values were found in a table table in the back of your statistics text labeled something like "areas under normal distribution."