Question

Researchers wanted to determine if there was an association between daily appleapple consumption and the occurrence of high cholesterolhigh cholesterol. The researchers looked at 94 comma 22894,228 women and asked them to report their appleapple?-eatingeating habits. The researchers also determined which of the women had high cholesterolhigh cholesterol. After their? analysis, the researchers concluded that consumption of two or more servingstwo or more servings of Granny Smith applesGranny Smith apples per day was associated with a reduction in high cholesterolhigh cholesterol. Complete parts? (a) through? (c) below. ?(a) What type of observational study was? this? Explain. A. This was a? case-control study because individuals that had a certain characteristic were matched with those that did not. B. This was a cohort study because it identified a group of individuals to participate in the study and observed the group over a long period of time. C. This was a? cross-sectional study because all information about the individuals was collected at a specific point in time. ?(b) What is the response variable in the? study? Is the response variable qualitative or? quantitative? What is the explanatory? variable? What is the response variable in the? study? Is the response variable qualitative or? quantitative? A. The response variable is consumption of Granny Smith applesGranny Smith apples. The response variable is quantitative. B. The response variable is the number of individuals who participate in the study. The response variable is quantitative. C. The response variable is the number of individuals who participate in the study who eateat two or more servingstwo or more servings of Granny Smith applesGranny Smith apples per day. The response variable is quantitative. D. The response variable is whether the woman has high cholesterolhigh cholesterol or not. The response variable is qualitative. What is the explanatory? variable? A. The explanatory variable is consumption of Granny Smith applesGranny Smith apples. B. The explanatory variable is the number of individuals who participate in the study who eateat two or more servingstwo or more servings of Granny Smith applesGranny Smith apples per day. C. The explanatory variable is the number of individuals who participate in the study. D. The explanatory variable is whether the woman has high cholesterolhigh cholesterol or not. ?(c) In their? report, the researchers stated that? "After adjusting for various demographic and lifestyle? variables, daily consumption of two or more servingstwo or more servings was associated with a? 30% reduced prevalence of high cholesterolhigh cholesterol?." Why was it important to adjust for these? variables? A. The researchers wanted to ensure that the sample was large enough in order to perform inference. B. The researchers may be concerned with confounding that occurs when the effects of two or more explanatory variables are not separated or when there are some explanatory variables that were not considered in a? study, but that affect the value of the response variable. C. The researchers were sure that various demographic and lifestyle variables had greater influence than daily consumption of two or more servingstwo or more servings. D. The researchers wanted to ensure that the study was representative of the entire? population, so they were likely to adjust the responses to match actual data collected for the entire population.

Answer 1

(a) What type of observational study was this?

This was a cross-sectional study because all information about the individuals was collected at a specific point in time.

(b) What is the response variable in the study? Is the response variable qualitative or? quantitative? What is the explanatory variable?

The response variable is whether the woman has high cholesterol or not.

The response variable is qualitative because we have to determine whether the women has high cholesterol or not.

The explanatory variable is the number of individuals who participate in the study who eat two or more servings of Granny Smith apples per day.

(c) In their report, the researchers stated that "After adjusting for various demographic and lifestyle? variables, daily consumption of two or more servingstwo or more servings was associated with a? 30% reduced prevalence of high cholesterolhigh cholesterol?." Why was it important to adjust for these variables?

The researchers may be concerned with confounding that occurs when the effects of two or more explanatory variables are not separated or when there are some explanatory variables that were not considered in a study, but that affect the value of the response variable.