Exam 12: Relationships Between Categorical Variables

For Questions use the following narrative Narrative: Aspirin and polyps A study done by the Ohio State University Medical Center examined whether or not taking an aspirin a day would help colon cancer patients reduce the chance of getting subsequent colon polyps.635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.54 patients in the aspirin group developed subsequent polyps, compared to 86 patients in the non-aspirin group.Many confounding variables were controlled for in this well-designed randomized experiment. -{Aspirin and polyps narrative} What is the baseline risk of developing subsequent polyps? Interpret your answer.

For Questions , use the following narrative Narrative: Aspirin and polyps A study done by the Ohio State University Medical Center examined whether or not taking an aspirin a day would help colon cancer patients reduce the chance of getting subsequent colon polyps.635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.54 patients in the aspirin group developed subsequent polyps, compared to 86 patients in the non-aspirin group.Many confounding variables were controlled for in this well-designed randomized experiment. -{Aspirin and polyps narrative} What percentage of all the patients in this study developed subsequent polyps?

A table that displays the number of individuals who fall into each combination of categorical variables is called a(n) __________ table.

When there is a treatment or behavior for which researchers want to study risk, they often compare it to the __________ risk, which is the risk without the treatment or behavior.

Suppose a new medical study at a research university shows that a woman's chance of developing breast cancer triples if she is overweight.You know that the American Cancer Society says that the chance of a woman developing breast cancer in her lifetime is 1 in 9.Does being overweight now increase a woman's chance to 1 in 3 of developing breast cancer?

For Questions use the following narrative Narrative: Aspirin and polyps A study done by the Ohio State University Medical Center examined whether or not taking an aspirin a day would help colon cancer patients reduce the chance of getting subsequent colon polyps.635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.54 patients in the aspirin group developed subsequent polyps, compared to 86 patients in the non-aspirin group.Many confounding variables were controlled for in this well-designed randomized experiment. -{Aspirin and polyps narrative} What is the relative risk of developing polyps for colon cancer patients who don't take an aspirin a day (compared to those who do)? Interpret your answer.

For Questions , use the following narrative Narrative: Talent and gender Suppose a talent contest is looking for people who can either sing or act.900 people tried out for the first round of auditions, 300 women and 600 men.Of the men who tried out, 55% of them were allowed to go on to the next round, compared to 42% of the women.However, if you break the data down by singing versus acting auditions, the relationship changes.For acting, 20% of the women made it through, compared to 15% of the men; for singing, 85% of the women made it through, compared to 75% of the men. -{Talent and gender narrative}What do we call this phenomenon, and how could this have happened?

For Questions , use the following narrative Narrative: Aspirin and polyps A study done by the Ohio State University Medical Center examined whether or not taking an aspirin a day would help colon cancer patients reduce the chance of getting subsequent colon polyps.635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.54 patients in the aspirin group developed subsequent polyps, compared to 86 patients in the non-aspirin group.Many confounding variables were controlled for in this well-designed randomized experiment. -{Aspirin and polyps narrative} Based on the results of this study, what can you conclude?

When researchers report relative risks and/or odds ratios, they often adjust them to account for __________.

One of the common ways the media misrepresent statistics about risk is that the reported risk is not necessarily your risk.What is the underlying problem that causes this?

For Questions , use the following narrative Narrative: Aspirin and polyps A study done by the Ohio State University Medical Center examined whether or not taking an aspirin a day would help colon cancer patients reduce the chance of getting subsequent colon polyps.635 patients with colon cancer participated; 317 of them were randomly assigned to the aspirin group, and the other 318 patients were assigned to a placebo (non-aspirin) group.54 patients in the aspirin group developed subsequent polyps, compared to 86 patients in the non-aspirin group.Many confounding variables were controlled for in this well-designed randomized experiment. -{Aspirin and polyps narrative} Which variable is the explanatory variable and which is the response variable in this study?

When omitting a third variable masks the relationship between two categorical variables, this phenomenon is called __________.

For Questions , use the following narrative Narrative: Genetic defect Suppose a population contains 100,000 individuals, of which 500 are carriers of a certain genetic defect. -{Genetic defect narrative}Which of the following is not an appropriate way to express this result as a portion of the total?

For Questions , use the following narrative Narrative: Blood clot risk Suppose you hear on the news that sitting on an airplane for five hours or more without getting up and walking around increases your chances of developing blood clots by 10 times. -{Blood clot risk narrative} The baseline risk is missing.Explain what that means in terms of what conclusions you can make about the results.

Which of the following is not one of the basic ways to express the chances that a randomly selected individual will fall into a particular category for a categorical variable?

Each row and column combination in a contingency table is called a(n) __________