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 3 inches. The heights of 10 randomly selected students are 74, 60, 71, 61, 70, 62, 69, 63, 70 and 69. D = Ex: 12.34+ Margin of error at 95% confidence level = Ex: 1.23 # 95% confidence interval = [ Ex: 12.34 Ex: 12 34 ] [smaller value. larger value] Check