Challenge activities CHALLENGE ACTIVITY 6.2.1: Confidence intervals for population means. 440338.2991490.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 6 inches. The heights of 7 randomly selected students are 74, 60, 71, 70, 68, 73 and 63. C = 68.43) Margin of error at 90% confidence level = Ex: 1.23 90% confidence interval = [ Ex: 12.34 Ex: 12.34 [smaller value, larger value] 1 2 Check Try again Feedback