Exercises

1.Explain the difference between an observational and an experimental study.

2.Name and define the three types of observational studies.

3.List some advantages and disadvantages of an observational study.

4.List some advantages and disadvantages of an experimental study. Page 3 of 9

5.What is the difference between an experimental study and a quasi-experimental study?

6.What is the difference between independent variables and dependent variables?

7.Why are a treatment group and a control group used in a statistical study?

8.Explain the Hawthorne effect.

9.What is a confounding variable?

10.Define the placebo effect in a statistical study.

11.What is meant by blinding and double-blinding?

12.Why do researchers use randomization in statistical studies?

13.What is the difference between a completely randomized design and a matched-pair design?

14.Why is replication used in statistical studies?

For Exercises 15-18, determine whether an observational study or an experimental study was used.

15.A survey was taken to see how many times in a month a person encountered a panhandler on the street.

16.A study using college students was conducted to see if the percentage of males who pay for a date was equal to the percentage of females who pay for a date.

17.A study was done on two groups of overweight individuals. Group 1 was placed on a healthy, moderate diet. Group 2 was not given any diet instructions. After 1 month, the members were asked how many times they engaged in binge eating. The results of the two groups were compared. 18.Two groups of students were randomly selected. The students in Group 1 were enrolled in the general studies program. Group 2 students were enrolled in a specific major program (i.e., business, engineering, social work, criminal justice, etc.). At the end of the first year of study, the grade point averages of the two groups were compared.

In Exercises 19-22, identify the independent variable and the dependent variable.

19.According to the British Journal of Sports Medicine, a regular 30-minute workout could slash your risk of catching a cold by 43%.

20.The Journal of Behavioral Medicine reported that sharing a hug and holding hands can limit the physical effects of stress such as soaring heart rate and elevated blood pressure.

21.A study was conducted to determine whether when a restaurant server drew a happy face on the check, that would increase the amount of the tip.

22.A study was conducted to determine if the marital status of an individual had any effect on the cause of death of the individual.

25 For Exercises 23-26, suggest some confounding variables that the researcher might want to consider when doing a study.

23.Psychology Today magazine reports that the more intelligent a person is (based on IQ), the more willing the person is to make a cooperative choice rather than a selfish one.

24.The New England Journal of Medicine reported that when poor women move to better neighborhoods, they lower the risk of developing obesity and diabetes.

25.A leading journal reported that people who have a more flexible work schedule are more satisfied with their jobs.

26.York University in Toronto, Canada, stated that people who had suffered from fibromyalgia were able to reduce their pain by participating in twice-weekly yoga sessions.

For Exercises 27-31, give a reason why the statement made might be misleading.

27.Our product will give you the perfect body.

28.Here is the whole truth about back pain.

29.Our pain medicine will give you 24 hours of pain relief.

30.By reading this book, you will increase your IQ by 20 points.

31.Eating 21 grams of fiber may help you to lose weight.

32.List the steps you should perform when conducting a statistical study.

33.Beneficial Bacteria According to a pilot study of 20 people conducted at the University of Minnesota, daily doses of a compound called arabinogalactan over a period of 6 months resulted in a significant increase in the beneficial lactobacillus species of bacteria. Why can't it be concluded that the compound is beneficial for the majority of people?

34.Comment on the following statement, taken from a magazine advertisement: "In a recent clinical study, Brand ABC (actual brand will not be named) was proved to be 1950% better than creatine!"

35.In an ad for women, the following statement was made: "For every 100 women, 91 have taken the road less traveled." Comment on this statement.

36.In many ads for weight loss products, under the product claims and in small print, the following statement is made: "These results are not typical." What does this say about the product being advertised?

37.In an ad for moisturizing lotion, the following claim is made: ". . . it's the number 1 dermatologist-recommended brand." What is misleading about this claim?

38.An ad for an exercise product stated: "Using this product will burn 74% more calories." What is misleading about this statement?

39."Vitamin E is a proven antioxidant and may help in fighting cancer and heart disease." Is there anything ambiguous about this claim?

Explain.

40."Just 1 capsule of Brand X can provide 24 hours of acid control." (Actual brand will not be named.) What needs to be more clearly defined in this statement?

41.". . . Male children born to women who smoke during pregnancy run a risk of violent and criminal behavior that lasts well into adulthood." Can we infer that smoking during pregnancy is responsible for criminal behavior in people?

42.Caffeine and Health In the 1980s, a study linked coffee to a higher risk of heart disease and pancreatic cancer. In the early 1990s, studies showed that drinking coffee posed minimal health threats. However, in 1994, a study showed that pregnant women who drank 3 or more cups of tea daily may be at risk for miscarriage. In 1998, a study claimed that women who drank more than a half-cup of caffeinated tea every day may actually increase their fertility. In 1998, a study showed that over a lifetime, a few extra cups of coffee a day can raise blood pressure, heart rate, and stress (Source: "Bottom Line: Is It Good for You? Or Bad?" by Monika Guttman, USA TODAY Weekend). Suggest some reasons why these studies appear to be conflicting.