Question

According to the article "Rubbing Hands Together Under Warm Air Dryers Can Counteract Bacteria Reduction"† washing your hands isn't enough—good "hand hygiene" also includes drying hands thoroughly. The article described an experiment to compare bacteria reduction for three different hand-drying methods. In this experiment, subjects handled uncooked chicken for 45 seconds, then washed their hands with a single squirt of soap for 60 seconds, and then used one of the three hand-drying methods. After completely drying their hands, the bacteria count on their hands was measured.

Suppose you want to carry out a similar experiment and that you have 30 subjects who are willing to participate. Describe a method for randomly assigning each of the 30 subjects to one of the hand-drying methods. (Select all that apply.)

A. Write the names of the thirty subjects on pieces of paper, then draw ten names for each of the treatments.

B. Choose two treatments and flip a coin to determine which treatment a subject is assigned to. When one of the treatments fills up, then assign them to the third treatment, until two treatments fill up. Assign the leftover subjects to the unfilled treatment.

C. Order the thirty subjects, then pick one of the first six subjects and choose every sixth subject after that for the first treatment. Repeat with a different one of the first six subjects for the second treatment, and do the same for the third treatment as well.

D. Choose two treatments and sort the subjects by gender. Then assign the men to one treatment and the women to the other treatment.

E. Order the thirty subjects and pick ten unique numbers using a random number generator to pick the subjects for the first treatment. Then pick ten more unique numbers for the second treatment, and assign the rest to the third treatment.

Answer 1

A. Write the names of the thirty subjects on pieces of paper, then draw ten names for each of the treatments

E. Order the thirty subjects and pick ten unique numbers using a random number generator to pick the subjects for the first treatment. Then pick ten more unique numbers for the second treatment, and assign the rest to the third treatment