Answer
$b = r\frac{s_{y}}{s_{x}} = 0.5 \frac{8}{40} = 0.1$
$a = \bar y - b \bar x = 75 - 0.1 \times 280 = 47$
$\hat y = 47 + 0.1x$
This implies that for each point increase in score of pre-exam, score of final exam will increase by 0.1 on average.
Work Step by Step
Given above