Suppose that Violet is conducting a study to determine whether there is a relationship between the time a person spends running and the number of calories that he or she burns. She selects a random sample of 40 runners between the ages of 18 and 24 and records the time that each person ran and the number of calories that each person was able to burn while running. At the end of her study, she finds that people who were able to run for longer times burned more calories. (a) What type of study is this? Briefly explain
(i) Experiment
(ii) Observational study
(iii) Survey
(b) What is the explanatory variable? Is it categorical or quantitative?
(c) What is the response variable? Is it categorical or quantitative?
(d) Which of the following is a potential lurking variable in this study? Defend your selection (i. e. explain why it is a lurking variable).
(i) the time each person ran
(ii) the number of calories each person burned
(iii) the age of the runners (iv) the speed at which each person ran