Answer
Here we have n = 654, x̅ = 26.8, s = 7.42, df = 653 and Confidence Level = 95%
Using online calculator, we have t = 1.964
$s_{x̅} = \frac{7.42}{\sqrt 654} = 0.29$
Lower Bound = 26.8 - (1.964)(0.29) = 26.3
Upper Bound = 26.8 + (1.964)(0.29) = 27.37
Work Step by Step
Given above