:Twl}.f:\" | 6.2.1: Confidence intervals for population means. 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 6 randomly selected students are 62, 74, 74, 66, 72 and 71. I =|Ex 12343 Margin of error at 95% confidence level = x: 1232 95% confidence interval = [ x 12343 Ex 12342 ] [smaller value, larger value] =