A sample of size $n = 50$ of the form $(x_i, y_i)$ for $i = 1, 2, \dots, 50$ was collected. The summary statistics are as follows:
$\sum_{i=1}^{n} x_i = 18$, $\sum_{i=1}^{n} y_i = 207$, $\sum_{i=1}^{n} x_i y_i = -3263$
$\sum_{i=1}^{n} x_i^2 = 1746$, $\sum_{i=1}^{n} y_i^2 = 7785$
A least-squares line was fitted and its equation is given by $\hat{y_i} = b_0 + b_1 x_i$. Also let $e_i = y_i - \hat{y_i}$ be the residual of the $i^{th}$ observation.