Start Suppose the mean height in inches of all 9th grade students at one high school is estimated. The population standard deviation is 4 inches. The heights of 8 randomly selected students are 67, 72, 73, 60, 72, 72, 68 and 60. a = EX: 12.34 Margin of error at 99% confidence level = Ex: 1.23 99% confidence interval = [ Ex: 12.34 Ex: 12.34 [smaller value, larger value] 1 2 Check Next ? 16 1 Provide feedback