Question A medical researcher was interested in determining

Question: A medical researcher was interested in determining how systolic blood pressure is affected by increased exertion during exercise for a sample of cardiac patients. She measured the systolic blood pressure of participants in the study as the speed of the treadmill on which they were walking was increased. Below is the scatterplot of the data for smokers and nonsmokers. How is the relationship between systolic blood pressure and speed of the treadmill affected by whether or not a participant smokes?

A. Whether or not a participant smokes does not affect the relationship between systolic blood pressure and speed of the treadmill

B. The systolic blood pressure for nonsmokers is higher than that of smokers

C. The regression equation explaining the relationship between systolic blood pressure and speed of the treadmill has a steeper slope for nonsmokers

D. The regression equation explaining the relationship between systolic blood pressure and speed of the treadmill has a steeper slope for smokers

E.There is a negative linear relationship between smoking and systolic blood pressure

Solution

D is the answer.

The points have aligned from bottom left to top right. This indicates that there is positive correlation between treadmill speed and systolic bp. All the points in red are above the black points which indicates that systolic bp is higher for smoker than non smokers.