A local tire dealer wants to predict the number of tires sold each month. The dealer believes that the number of tires sold is a linear function of the amount of money invested in advertising. The dealer randomly selects 6 months of data consisting of tire sales (in thousands of tires) and advertising expenditures (in thousands of dollars). Based on the data set with 6 observations, the simple linear regression model yielded the following results.
$$\sum x$$ = 24 $$\sum X ^ { 2 }$$ =124 $$\sum Y$$ =42 $$\sum Y ^ { 2 }$$ =338 $$\sum X Y$$ =196
-What is the degrees of freedom value associated with the error sum of squares,or unexplained variation?
A)1
B)2
C)3
D)4
E)5

Question

Quizplus · Accepted Answer

The degrees of freedom for the error sum of squares in a simple linear regression model is calculated as $n - 2$, where $n$ is the number of observations. Here, $n = 6$, so the degrees of freedom for the error sum of squares is $6 - 2 = 4$.

A Local Tire Dealer Wants to Predict the Number of Tires