Linear Regression & Least Squares Method: Videos & Practice Problems

A company uses a regression equation $\hat{y}=120-0.8x$ to predict monthly expenses ($y$) based on the number of units produced ($x$). For a sample of $n=20$ months, $\bar{x}=50$, $S_{xx}=500$, and the standard error of estimate is $s_y=12$. Construct a $90\%$ prediction interval for monthly expenses when $60$ units are produced.