Answer
We are 95% confident that the mean number of shares of Pepsico traded per day in 2010 is between 4.95 million and 5.91 million.
Work Step by Step
Here we have n = 40, df = n-1 = 39, x̅ = 5.43 and s = 1.48
Confidence = 95%
α = 1 - 0.95 = 0.05, α/2 = 0.025, $t_{α/2} = 2.023$
$E = 2.023 \times \frac{1.48}{\sqrt39} = 0.479 $
Lower Bound = x̅ - E = 5.43 - 0.479 = 4.95
Upper Bound = x̅ + E = 5.43 + 0.479 = 5.91
