CHALLENGE ACTIVITY 6.2.1: Confidence intervals for population means. 402294.2602416.qx3zqy7 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 4 inches. The heights of 6 randomly selected students are 63, 65, 62, 71, 61 and 66. C = 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