CHAPTER 7
Two-Variable Data Analysis
In the scatterplot, the dashed lines represent the mean values of the two variables. Removing point A
would have which of the following effects?
(A) The slope of the regression line would increase, and the correlation would decrease.
(B) The slope of the regression line would decrease, and the correlation would increase.
(C) The slope of the regression line would not change, and the correlation would increase.
(D) The slope of the regression line would not change, and the correlation would decrease.
(E) Neither the slope of the regression line nor the correlation would change.
- A statistics professor has collected data over the years on the midterm exam and final exam scores
for his students. There is a positive linear association between the two sets of scores, and the
correlation is 0.73. The standard deviation of midterm scores is 15 points, and the standard deviation
of final exam scores is 25 points. If a student scores 18 points above the mean score on her midterm
exam, about how far above the mean final exam score is her predicted final exam score?
(A) 18 points
(B) 22 points
(C) 30 points
(D) She would be predicted to get 0 points on the final exam.
(E) It is impossible to calculate this without knowing the mean scores.