Exam 17: Turning Information Into Wisdom

Use the following information for questions: In a report by ABC News, the headlines read "City Living Increases Men's Death Risk" The headlines were based on a study of 3,617 adults who lived in the United States and were more than 25 years old. One researcher said, "Elevated levels of tumor deaths suggest the influence of physical, chemical and biological exposures in urban areas… Living in cities also involves potentially stressful levels of noise, sensory stimulation and overload, interpersonal relations and conflict, and vigilance against hazards ranging from crime to accidents." -What type of study was this?

Use the following information for questions: In a report by AP, the headline read "Even light weekend use of the party drug Ecstasy might harm intelligence, a study suggests". The headline was based on a study of 28 Ecstasy users in their mid-20s recruited off the dance floor of a nightclub. The researchers compared this group with two others of the same size, age range, and education level - one consisting of drug-free people and another of people who smoked about as much marijuana as the Ecstasy group. The researchers reported weeks after partying, those who used Ecstasy along with marijuana performed worse on intelligence tests than people who just smoked marijuana or took no drugs at all. -What was the explanatory variable?

A small college wants to know what percentage of its current 2,500 students wants a switch to a quarter system. Every student in the college is polled with a question attached to the course registration form. What's the margin of error for the poll?

Use the following information for questions: In a report by ABC News, the headlines read "City Living Increases Men's Death Risk" The headlines were based on a study of 3,617 adults who lived in the United States and were more than 25 years old. One researcher said, "Elevated levels of tumor deaths suggest the influence of physical, chemical and biological exposures in urban areas… Living in cities also involves potentially stressful levels of noise, sensory stimulation and overload, interpersonal relations and conflict, and vigilance against hazards ranging from crime to accidents." -What was a potential confounding variable?

One problem with hypothesis testing is that a result may be statistically significant but be of little practical significance. This problem is most likely to occur when

Use the following information for questions: In a report by ABC News, the headlines read "City Living Increases Men's Death Risk" The headlines were based on a study of 3,617 adults who lived in the United States and were more than 25 years old. One researcher said, "Elevated levels of tumor deaths suggest the influence of physical, chemical and biological exposures in urban areas… Living in cities also involves potentially stressful levels of noise, sensory stimulation and overload, interpersonal relations and conflict, and vigilance against hazards ranging from crime to accidents." -What was the explanatory variable?

The margin of error for the results of a survey takes into account

Use the following information for questions: In a report by CNN Health News, the headlines read "Study: Junk food raises teens' risk of heart disease." The headlines were based on a study of 249 high school students between the ages of 13 and 18. One researcher said, "more than 80% of those tested were eating a diet that could promote heart disease." Ultrasound was used to measure the thickness of the carotid artery, which, the researcher said, "can be an early indicator of atherosclerosis, an abnormal hardening of the artery walls." -The conservative margin of error for the sample of 249 students is

Use the following information for questions: In a report by ABC News, the headlines read "City Living Increases Men's Death Risk" The headlines were based on a study of 3,617 adults who lived in the United States and were more than 25 years old. One researcher said, "Elevated levels of tumor deaths suggest the influence of physical, chemical and biological exposures in urban areas… Living in cities also involves potentially stressful levels of noise, sensory stimulation and overload, interpersonal relations and conflict, and vigilance against hazards ranging from crime to accidents." -What was the response variable?

Use the following information for questions: An observational study found a statistically significant relationship between regular consumption of tomato products (yes, no) and development of prostate cancer (yes, no), with lower risk for those consuming tomato products. -Setting aside the feasibility of doing so, suppose the results had been based on a randomized experiment (instead of an observational study), in which men were randomly assigned to consume or abstain from tomato products. Which of the following problems associated with observational studies would no longer be a problem?

CNN reported the results of a survey of 902 adult Americans taken to assess whether Americans think there should be stronger gun control laws. The margin of error was reported to be 3%. Which choice best describes how to interpret the 3% margin of error?

Use the following information for questions: In a report by CNN Health News, the headlines read "Study: Junk food raises teens' risk of heart disease." The headlines were based on a study of 249 high school students between the ages of 13 and 18. One researcher said, "more than 80% of those tested were eating a diet that could promote heart disease." Ultrasound was used to measure the thickness of the carotid artery, which, the researcher said, "can be an early indicator of atherosclerosis, an abnormal hardening of the artery walls." -Is a conclusion that a junk food diet causes an increased risk of heart disease justified?

An observational study found that people who listened to classical music regularly had statistically significantly lower average blood pressure than those who didn't listen to classical music. Which one of the following headlines is justified?

Use the following information for questions: A random sample of 600 students was asked whether student fees should be used to construct a new football stadium. -The conservative margin of error for the sample of 600 students is

Use the following information for questions: In a report by CNN Health News, the headlines read "Study: Junk food raises teens' risk of heart disease." The headlines were based on a study of 249 high school students between the ages of 13 and 18. One researcher said, "more than 80% of those tested were eating a diet that could promote heart disease." Ultrasound was used to measure the thickness of the carotid artery, which, the researcher said, "can be an early indicator of atherosclerosis, an abnormal hardening of the artery walls." -What was the response variable?

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. -Can a conclusion be made that mothers who worked during the first nine months after having a child caused the lower scores seen at 36 months?

You are asked to serve on a jury for a trial to decide whether a defendant is guilty of murder. You will decide either that the defendant is guilty or not guilty. Explain what your Type 1 and Type 2 errors are.

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". -What was the explanatory variable?

The best way to determine whether a statistically significant difference in two means is of practical importance is to

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". -What was the response variable?