A survey of 100 commuters finds the average commuting to work is 25.5 minutes with the standard deviation of 11.5 minutes. construct a 98% confidence interval for the mean commuting time of commuters

answer: 100%-98%=2%=0.02=0.01=1.28
E=1.28.11.5 divide by 10= 1.47
(25.5-1.47, 25.5+ 1.47)= (24.3, 26.97)