Exam 6: Gathering Useful Data for Examining Relationships

A distortion of results caused by the response of subjects to the special attention they receive from researchers is called

You wish to study the effect of a tutoring program to help improve student grades in an introductory statistics course. Propose a prospective study design to answer the question.

Use the following information for questions: A researcher wishes to see whether there is any difference in the average weight gains of athletes following one of three special diets (Diet 1, Diet 2, and Diet 3). The initial study design was to randomly assign the athletes to one of the three diet groups and place them on the diet for six weeks. The weight gain (in pounds) at the end of the six weeks would be recorded for each athlete. -Gender was also recorded for this study. The results showed that the amount by which the weight gains for the three diets differed was affected by whether the athlete was a male or female. What is the statistical name for the variable gender in this case?

Use the following information for questions: For each relationship (conclusions from one or more studies), define what the response and explanatory variables are. -Second hand smoke (passive smoke) is a risk factor for chronic lung disease.

Use the following information for questions: For each relationship (conclusions from one or more studies), define what the response and explanatory variables are. -Children who take the time to eat breakfast get higher grades in school than children who don't eat breakfast.

Which of the following methods is not a good randomization procedure?

A tea manufacturer is trying to decide whether to add peach flavoring or mango flavoring to green tea for a new product. A study is done by stopping customers at a grocery store and asking them to drink a small cup of tea with each flavoring, then to rate each of the two flavors on a scale from 1 to 10. The order in which the teas are presented is randomly assigned for each person. What type of study is this?

Eighty individuals who wished to lose weight were randomly divided into two groups of 40. One group was given an exercise program to follow while the other group was given a special diet. After three months, the researcher compared mean weight losses in the two groups. What type of study is this?

Which of the following is true about confounding variables in observational studies?

Use the following information for questions: For each relationship (conclusions from one or more studies), define what the response and explanatory variables are. -Drinking as little as two cups of coffee before exercising limits the blood flow to the heart. An experiment with 18 young adults showed that when the subject remained inactive, the caffeine had very little affect, but after the subject participated in exercise, the caffeine slowed down the blood flow to the heart.

A difficult birth may put a baby at greater risk for autism, according to a study that may provide clues to the causes of the devastating neurological disability. The Centers for Disease Control and Prevention said that in a study of 698 Danish children who had the developmental disorder (autism), researchers found a disproportionately high number had been born before the 35^th week of pregnancy, had suffered from low birth weights and were in a breech position at birth. What type of study is this?

Use the following information for questions: Researchers would like to compare meditation and exercise to see which is more effective for reducing stress. One hundred people who suffer from high stress volunteer to participate in a study for ten weeks. Participants will either be given a 10-week course in meditation or will participate in a 10-week exercise program. The researchers must decide whether to randomly assign the volunteers to the two programs, or allow them to choose. -Suppose participants are randomly assigned to the two programs and a psychologist measures their stress levels before and after the 10-week program, without being told who is in which program. This experiment would be

Use the following information for questions: A difficult birth or a history of mental illness in a parent may put a baby at greater risk for autism. The Centers for Disease Control and Prevention said that in a study of 698 Danish children with the developmental disorder, researchers found a disproportionately high number had been born before the 35th week of pregnancy, had suffered from low birth weights and were in a breech position at birth. The children, all of whom were born after 1972 and diagnosed with autism before 2000, also were more likely to have a parent who had been diagnosed with schizophrenia-like psychosis before the autism was discovered. -What type of study is this?

In a study of acupuncture for treating pain 100 patients were recruited. Half were randomly assigned to receive acupuncture and the other half to receive a sham acupuncture treatment. The patients were followed for 6 months and the degree of pain relief measured. The patients did not know which treatment they actually received, but the treating physicians were aware of who was getting acupuncture and who wasn't. Which of the following does not apply to this study?

A medical doctor is comparing two treatments for high cholesterol. She puts the names of 40 patients with high cholesterol into a box, and randomly draws the names of 20 patients. These 20 patients are given treatment 1. The doctor gives treatment 2 to the remaining 20 patients. What type of study design is this?

Use the following information for questions: Having a coffee fix just before a workout may not be the best idea, a study suggests. Researchers in Switzerland found that the amount of caffeine in just two cups of coffee limits the body's ability to increase blood flow to the heart during exercise. The study included 18 young, healthy people who were regular coffee drinkers. They did not drink any coffee for 36 hours prior to study testing. The researchers used high-tech PET scans to measure the participants' heart blood flow before and after they rode a stationary bike and then repeated the testing procedure after swallowing a tablet containing 200 milligrams of caffeine -- the amount contained in two cups of coffee. The caffeine did not affect heart blood flow when the participants were inactive. However, measurements taken immediately after exercise showed a slowdown in heart blood flow after they'd taken the caffeine tablets, compared to their previous results. -What type of study is this?

A survey of 1,204 black respondents found that 31% agreed with the statement "American society is fair to everyone" when the race of the interviewer was white, but only 14% agreed when the race of the interviewer was black. The difference between these responses is an example of

Use the following information for questions: Sickle-cell disease is a painful disorder of the red blood cells that in the United States affects mostly blacks. To investigate whether drug A can reduce the pain associated with sickle-cell disease, a study by the National Institutes of Health randomly assigned 150 sickle-cell sufferers to receive the drug. Placebos were given to another 150 sickle-cell sufferers. Great care was used to ensure that the 300 participants did not know if their pill contained the drug. At the end of the treatment period, the researchers counted the number of episodes of pain reported by each subject. -What type of study is this?

In a Gallup telephone survey of 1001 adults done before the Thanksgiving holiday, 58% said they would like to lose a few pounds. Which of the following applies to this study?

If a statistically significant relationship is found in an observational study for which the sample represents the population of interest, then which of the following is true?