A researcher wants to investigate the effectiveness of a cholesterol-lowering medication.The 450 participants are first divided into two groups - those suffering from diabetes and those not suffering from diabetes.Within each group the participants are randomly assigned to one of three groups.The first group will receive a low dose of the medication,the second group will receive a high dose of the medication,and the third group will receive a placebo.At the end of a six-month period,each person's cholesterol will be tested and the change in their cholesterol level will be recorded.Identify the factor(s) and any blocking variables and the number of levels for each.

A) Factor: Medication (3 levels) ,Factor: diabetes (2 levels)
B) Factor: Diabetes,no diabetes (2 levels)
C) Factor: Medication (3 levels) ,Blocking variable: diabetes (2 levels)
D) Factor: Placebo,low dose of medication,high dose of medication (3 levels)
E) Factor: Placebo and diabetes,low dose of medication and diabetes,high dose of medication and diabetes,placebo and no diabetes,low dose of medication and no diabetes,high dose of medication and no diabetes (6 levels)

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Nathan Oxley · Accepted Answer

Final Answer : C, Explanation :  The factor of interest is the medication with three levels (placebo, low dose, high dose) and the blocking variable is diabetes with two levels. This design allows for separate analysis of the effect of medication within each level of diabetes, while controlling for the potential confounding effects of diabetes status. This results in a more precise estimation of the medication effect, making it the best choice.

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