You wonder whether green tea lowers cholesterol. Complete parts (a) through (h) below (a) To research...

 

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You wonder whether green tea lowers cholesterol. Complete parts (a) through (h) below (a) To research the claim that green tea lowers LDL (so-called bad) cholesterol, you ask a random sample of individuals to divulge whether they are regular green tea users or not. You also obtain their LDL cholesterol levels. Finally, you compare the LDL cholesterol levels of the green tea drinkers to those of the non-green tea drinkers. Explain why this is an observational study. OA. This is an observational study because the researcher is manipulating the explanatory variable, whether the individual is a green tea drinker or not. OB. This is an observational study because the researcher is manipulating the explanatory variable, LDL cholesterol levels. OC. This is an observational study because there is no intent to manipulate the explanatory variable, LDL cholesterol levels. OD. This is an observational study because there is no intent to manipulate the explanatory variable, whether the individual is a green tea drinker or not (b) Name some lurking variables that might exist in the study. Select all that apply. A Gender B. Exercise C. Diet D. Genetics E Number of siblings F. Age (c) Suppose, instead of surveying individuals regarding their tea-drinking habits, you decide to conduct a designed experiment. You identify 120 volunteers to participate in the study and decide on three levels of the treatment a placebo, one cup of green tea daily, two cups of green tea daily. The experiment is to run for one year. The response variable will be the change in LDL cholesterol for each subject from the beginning of the study to the end. What type of experimental design is this? 0000 Case-control study Randomized block design Completely randomized design Matched-pairs design (d) Explain how you would use blinding in this experiment OA. Do not allow the subjects to know which level of the treatment they are receiving. Also, do not allow the researcher(s) giving the treatments to know which level of the treatment they are giving. This is a double-blind study. OB. Do not allow the subjects to know which level of the treatment they are receiving. This is a double-blind study. OC. Do not allow the researcher(s) giving the treatments to know which level of the treatment they are giving. This is a single-blind study. OD. Split up both the males and females equally into the three different treatment groups. O E. Blinding is not possible in this experiment. (e) What is the factor? Is it qualitative or quantitative? The factor is It is (What factors might you attempt to control in this experiment? Select all that apply A Diet B. Genetics C. Exercise D. Age E. Number of siblings F. Gender (g) Explain how to use randomization in this experiment. How does randomization neutralize those variables that are not controlled? to treatment groups. This will mute the effect of variation attributable to the Randomly assign the Then any difference in the value of the response variable among the different treatment groups is a result of that are not controlled. (h) Suppose you assigned 40 subjects to each of the three treatment groups. In addition, you decided to control the variable exercise by having each subject perform 150 minutes of cardiovascular exercise each week by walking on a treadmill. However, the 40 subjects in the placebo group decided they did not want to walk on the treadmill and skipped the weekly exercise. Explain how exercise is now a confounding variable. Any difference in the change in the cannot be attributed to the It may be the that caused the change in the You wonder whether green tea lowers cholesterol. Complete parts (a) through (h) below (a) To research the claim that green tea lowers LDL (so-called bad) cholesterol, you ask a random sample of individuals to divulge whether they are regular green tea users or not. You also obtain their LDL cholesterol levels. Finally, you compare the LDL cholesterol levels of the green tea drinkers to those of the non-green tea drinkers. Explain why this is an observational study. OA. This is an observational study because the researcher is manipulating the explanatory variable, whether the individual is a green tea drinker or not. OB. This is an observational study because the researcher is manipulating the explanatory variable, LDL cholesterol levels. OC. This is an observational study because there is no intent to manipulate the explanatory variable, LDL cholesterol levels. OD. This is an observational study because there is no intent to manipulate the explanatory variable, whether the individual is a green tea drinker or not (b) Name some lurking variables that might exist in the study. Select all that apply. A Gender B. Exercise C. Diet D. Genetics E Number of siblings F. Age (c) Suppose, instead of surveying individuals regarding their tea-drinking habits, you decide to conduct a designed experiment. You identify 120 volunteers to participate in the study and decide on three levels of the treatment a placebo, one cup of green tea daily, two cups of green tea daily. The experiment is to run for one year. The response variable will be the change in LDL cholesterol for each subject from the beginning of the study to the end. What type of experimental design is this? 0000 Case-control study Randomized block design Completely randomized design Matched-pairs design (d) Explain how you would use blinding in this experiment OA. Do not allow the subjects to know which level of the treatment they are receiving. Also, do not allow the researcher(s) giving the treatments to know which level of the treatment they are giving. This is a double-blind study. OB. Do not allow the subjects to know which level of the treatment they are receiving. This is a double-blind study. OC. Do not allow the researcher(s) giving the treatments to know which level of the treatment they are giving. This is a single-blind study. OD. Split up both the males and females equally into the three different treatment groups. O E. Blinding is not possible in this experiment. (e) What is the factor? Is it qualitative or quantitative? The factor is It is (What factors might you attempt to control in this experiment? Select all that apply A Diet B. Genetics C. Exercise D. Age E. Number of siblings F. Gender (g) Explain how to use randomization in this experiment. How does randomization neutralize those variables that are not controlled? to treatment groups. This will mute the effect of variation attributable to the Randomly assign the Then any difference in the value of the response variable among the different treatment groups is a result of that are not controlled. (h) Suppose you assigned 40 subjects to each of the three treatment groups. In addition, you decided to control the variable exercise by having each subject perform 150 minutes of cardiovascular exercise each week by walking on a treadmill. However, the 40 subjects in the placebo group decided they did not want to walk on the treadmill and skipped the weekly exercise. Explain how exercise is now a confounding variable. Any difference in the change in the cannot be attributed to the It may be the that caused the change in the

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a This is an observational study because the researcher is not manipulating the explanatory variable ... View the full answer