Case Study 1.5 (p. 5) was called “Does Prayer Lower Blood Pressure?” One of the results quoted in that study was,

“People who attended a religious service once a week and prayed or studied the Bible once a day were 40% less likely to have high blood pressure than those who don’t go to church every week and prayed and studied the Bible less.”

a. What is the explanatory variable in this study?

b. What is the response variable in this study?

c. Give an example of a third variable that might at least partially account for the observed relationship.