Exam 17: Turning Information Into Wisdom

A researcher compares two different treatments for depression. The result is not statistically significant so the researcher says that the two treatments are equally effective. Which one of the following statements is correct?

An observational study found a statistically significant relationship between an explanatory variable and a response variable that surprised the researchers. If you wanted to explore possible explanations, which of the following pieces of information would not be useful?

Use the following information for questions: In a report by Reuters, the headline read "Emotional Support Helps Breast Cancer Survival" The headline was based on a study of 847 women (442 black women and 405 white women) with breast cancer and how they fared over a 9-year period. The authors wrote "Women in our study who reported low levels of both emotional expression and emotional support experienced 2 to 4 times greater breast cancer mortality than women reporting high levels of both". -The conservative margin of error for the sample of 847 women is

Use the following information for questions: In a report by Reuters, the headline read "Emotional Support Helps Breast Cancer Survival" The headline was based on a study of 847 women (442 black women and 405 white women) with breast cancer and how they fared over a 9-year period. The authors wrote "Women in our study who reported low levels of both emotional expression and emotional support experienced 2 to 4 times greater breast cancer mortality than women reporting high levels of both". -Is a conclusion that more emotional support causes a reduction in breast cancer mortality justified?

Use the following information for questions: 43 sedentary adults between the ages of 50 and 76 were randomly assigned to either an exercise program four times a week for 16 weeks or they continued to be sedentary (King, et al, JAMA, January 1, 1997,pp 32-37). The exercise group slept an average of 42 minutes a night longer than the control group. -What is the response variable in the study?

Suppose you are faced with a decision about whether to take a new job or remain with the one you have. In an analogy to hypothesis testing, the alternative hypothesis is that you will be better off if you change jobs. Your friends are encouraging you to take the new job. In statistical terms, they think:

One problem with hypothesis testing is that a real effect may not be detected. This problem is most likely to occur when

Use the following information for questions: A random sample of 500 students showed a statistically significant relationship between where the students usually sat in class (front, middle, or back) and grade point average (GPA). -What is the explanatory variable in the study?

An ABC news poll over the Internet resulted in 17,251 responses. Explain why the results of this poll should not be generalized to the American population.

Use the following information for questions: In a study of 900 European American children born in 1991 ("Maternal Employment and Child Cognitive Outcomes in the First Three Years of Life: The NICHD Study of Early Child Care," Brooks-Gunn, Han, and Waldfogel, Child Development 73[2002]: 1052-1072), the authors wrote "children whose mothers worked at all by the ninth month of their life had lower [cognitive outcome] scores at 36 months than did children whose mothers did not work by that time." These results were statistically significant. -What is the explanatory variable in this study?