91Ó°ÊÓ

Given in the question that, Home Size and Value. The data from Exercise 14.38 for home size (in square feet) and assessed value (in thousands of dollars) for the same homes as in Exercise 14.73 are on the WeissStats site. We need to decide that whether we can reasonably apply the regression t-lest. If so, then also do part (b).

Given,

MINITAB is used to create the residual plot.

Procedure with Minitab:

First, select Start > Regression > Regression.

Step 2: In the Response box, type VALUE in the Column field.

Step 3: Select Column HOME SIZE in Predictors.

Step 4: In Graphs, under Residuals vs the variables, enter the columns HOME SIZE.

Step 5: Click the OK button.

OUTPUT FROM MINITAB:

MINITAB is used to create a normal probability plot of residuals.

Procedure with Minitab:

First, select Start > Regression > Regression.

Step 2: In the Response box, type VALUE in the Column field.

Step 3: Select Column HOME SIZE in Predictors.

Step 4: Select Normal probability plot of residuals from the Graphs menu.

Step 5: Click the OK button.

OUTPUT FROM MINITAB:

The following is the assumption for regression inferences:

Line of population regression:

For each value $X$of the predictor variable, the conditional mean of the response variable $\left(Y\right)$is $\mathrm{β}0+\mathrm{β}1X$.

The standard deviation for the response variable $(Y)$ and the standard deviation for the explanatory variable $(X)$ are the same. The standard deviation is represented by the symbol $\sigma$.

Populations that are typical:

The response variable follows a normal distribution.

Independent Observations: The responses variable observations are unrelated to one another.

Examine whether the regression t-test is appropriate.

• It's evident from the residual plot that the residuals are in the horizontal band.
• It is obvious from the normal probability plot of residuals that the residuals do not follow the linear pattern.