Question

Gas Guzzlers. The data from Exercise 14.41 for gas mileage and engine displacement of 121 vehicles are on the WeissStats site.Do the data provide sufficient evidence to conclude that engine displacement and gas mileage are negatively linearly correlated?

Short answer

It is not reasonably apply the correlation$t$-test procedure.

Step-by-step solution

Step 1:Given informatiion

The data from Exercise 14.41 for gas mileage and engine displacement of 121 vehicles are on the WeissStats site.

Step 2:Explainaton

Check whether or not it is reasonably apply the correlation t-test procedure by using the data from Exercise 14.41.

- From the residual plot versus engine displacement, there is concave upward curve pattern.

- From the normal probability plot of residuals and the residual plot, it is clear that there is presence of outliers in the data. Therefore, the linear model is inappropriate.

Hence, the assumption 1 for the regression inferences is violated for the variables Mpg and disp.

Therefore, it is not reasonably apply the correlation$t$-test procedure.