Start Suppose the mean height in inches of all 9th grade students at one high school is estimated. The population standard deviation is 6 inches. The heights of 8 randomly selected students are 66, 68, 72, 71, 75, 69, 73 and 61. a = Ex: 12:34 Margin of error at 90% confidence level = Ex: 1.23 90% confidence interval = [ Ex. 12.34 Ex 12 34 ] [smaller value, larger value] 2 Check Next