Confidence intervals for population means.

Suppose the mean height of all 9th grade students at one high school is estimated. The population standard deviation is 3 inches. The Height of 9 randomly selected students are 66, 64, 64, 60, 61, 75, 61, 69, and 67.

x= ?

margin of error at 95% confidence level =?

95% confidence interval = [ , ]

[ smaller value, larger value]