EVEN NUMBER ONLY!!!! for 24-28 determine whether the study is an experiment or observational study, and then identify a major problem with the study.

1-3 Collecting 24. Blood Pressure A medical researcher tested for a difference in systolic blood pressure levels between male and female students who are 20 years of age. She randomly selected four males and four females for her study. 25. Salt Deprivation In a program designed to investigate the effects of salt deprivation in diets, the original plan was to use a sample of 500 adults randomly selected throughout the country. The program managers know that they would get a biased sample if they limit their study to adults in New York City, so they planned to compensate for that bias by using a larger sample of 2000 adults in New York City. 26. Atkins Weight Loss Program An independent researcher tested the effectiveness of the Atkins weight loss program by randomly selecting 1000 subjects using that program. Each of the subjects was called to report his or her weight before the diet and after the diet. 27. Crime Research A researcher has created a brief survey to be given to 2000 adults ran- domly selected from the U.S. population. Here are her first two questions: (1) Have you ever been the victim of a felony crime? (2) Have you ever been convicted of a felony? 28. Medications The Pharmaceutical Research and Manufacturers of America wants infor- mation about the consumption of various medications. An independent researcher conducts a survey by mailing 10,000 questionnaires to randomly selected adults in the United States, and she receives 152 responses. 1-3 Beyond the Basics In Exercises 29-32, indicate whether the observational study used is cross-sectional, retrospective, or prospective. 29. Nurses' Health Study II Phase II of the Nurses' Health Study was started in 1989 with 116,000 female registered nurses. The study is ongoing. 30. Heart Health Study Samples of subjects with and without heart disease were selected, then researchers looked back in time to determine whether they took aspirin on a regular basis. 31. Marijuana Study Researchers from the National Institutes of Health want to determine the current rates of marijuana consumption among adults living in states that have legalized the use of marijuana. They conduct a survey of 500 adults in those states. 32. Framingham Heart Study The Framingham Heart Study was started in 1948 and is ongo- ing. Its focus is on heart disease