Exam
Name___________________________________

SHORT ANSWER.  Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response.
1) The following residual plot is obtained after a regression equation is determined for a set of data. Does the residual plot suggest that the regression equation is a bad model? Why or why not?
	1)  _____________

2) The following residual plot is obtained after a regression equation is determined for a set of data. Does the residual plot suggest that the regression equation is a bad model? Why or why not?
	2)  _____________

1) No, the residual plot does not suggest that the regression equation is a bad model.  The residual plot does not have an obvious pattern that is not a straight line.  This confirms that a scatterplot of the sample data is a straight line. The residual plot does not become thicker or thinner when viewed from left to right. This confirms that for different fixed values of x, the distributions of the corresponding y-values all have the same standard deviation.
2) Yes, the residual plot suggests that the regression equation is a bad model. The residual plot  becomes thinner when viewed from left to right. This suggests that for different fixed values of x, the distributions of the corresponding y-values  have different standard deviations.