12. Regression

Which of the following residual plots suggest that a linear regression model is appropriate?

In the context of regression analysis, what is a residual, and what does it indicate when a residual is positive? (A residual is typically defined as $e=y-\hat{y}$, where $y$ is the observed value and $\hat{y}$ is the predicted value.)

In the context of residuals analysis, what does a residual value of $-0.8$ indicate about a data point relative to the line of best fit?

Which of the following patterns in a residual plot indicates that the line of best fit is appropriate for the data?