Posted by sue on Thursday, December 19, 2013 at 8:54pm.
For these 90 times the mean was 15.60 minutes and the standard deviation s=1.80 minutes. Find the margin of error (round to 2 decimal places) and the 95% confidence interval for Julia’s average running time.

statistics  Kuai, Thursday, December 19, 2013 at 9:01pm
Margin of error : 0.372
95 % confidence interval. (15.228, 15.972)