The progress of a type of cancer differs in women and men. A clinical experiment to compare four therapies for this cancer therefore treats sex as a blocking variable.
500 male and 300 female patients have agreed to act as subjects. Which of the following approaches will you use to create a block design for the experiment?
A.
Observe the current state of cancer. Split the subjects into two groups using sex as the blocking variable and then randomly assign subjects in each group into four sub-groups. Assign each sub-group to one of the treatments. Observe the progress of cancer.
B.
Observe the current state of cancer. Randomly assign subjects to two groups and using sex as the blocking variable, split each group to two sub-groups. Assign each sub-group to one of the treatments. Observe the progress of cancer.
C.
Observe the current state of cancer. Assign the subjects to the four treatments in one randomization. Observe the progress of cancer for male and female subjects.
Answer: A.
Observe the current state of cancer. Split the subjects into two groups using sex as the blocking variable and then randomly assign subjects in each group into four sub-groups. Assign each sub-group to one of the treatments. Observe the progress of cancer.
If the answers is incorrect or not given, you can answer the above question in the comment box. If the answers is incorrect or not given, you can answer the above question in the comment box.