Answer
We fail to reject the Null hypothesis as 45 is present in the confidence interval.
Work Step by Step
n = 40, x̅ = 48.3, s = 8.5 and α = 0.01
From Table-VI, we have: $t_{α/2} = 2.708$
$E = 2.708 \times \frac{8.5}{\sqrt 40} = 3.639$
Lower Bound = 48.3 - 3.639 = 44.66
Upper Bound = 48.3 + 3.639 = 51.94
