Jump to level 1 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 9 randomly selected students are 66, 67, 65, 75, 69, 72, 61, 60 and 60. C= 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]