Last year, five randomly selected business students took a statistics aptitude test before they began their

business course. In the table below, the $x$ column shows scores on the statistics aptitude test. Similarly, the

y column shows business grades.

The Business School has three questions:

$($a$)$ What linear regression equation best predicts business performance, based on statistics aptitude scores?

$($b$)$ If a student made an $80$ on the statistics aptitude test, what grade would we expect her to make in business

test?

$($c$)$ How well does the regression equation fit the data?