Determine the point estimate of the population mean and marg

Determine the point estimate of the population mean and margin of error for the confidence interval. Lower bound is 18, upper bound is 28.

Solution

Let x-bar be the sample mean and SE be the standard error. x-bar - (1.96) SE = 18 ------(1) x-bar + (1.96) SE = 24 ------(2) Add (1) and (2): 2 x-bar = 42 x-bar = 21 ----- sample mean (point estimate of the population mean) Subtract (2) from (1) -2(1.96) SE = -6 SE = 6/(2(1.96)) SE = 1.5306 Margin of error = (1.96)SE = (1.96)(1.5306) = 2.9999 = +/- 3