A track and field coach wants to analyze the effect of sportsdrinks on the performance of his athletes. He decides to test threebrands: Powerade, Gatorade and Vitaminwater. He will have each ofthe athletes complete a 400 meter run and record their times. Whichof the following represents a blocked design? Mark all thatapply.

A) He decides to give all male athletes Gatorade and the femaleathletes either Powerade or Vitaminwater.

B) He has some of the athletes drink the sports drink two hoursbefore running, and others one hour before running.

C) He has some of the athletes drink Gatorade two hours beforerunning, others drink Powerade one hour before running, and therest Vitaminwater half an hour before running.

He has some of the athletes run in the morning, some midday andsome in the afternoon.

D) He has some of the athletes drink Vitaminwater and run in themorning, some drink Gatorade and run midday and some drink Poweradeand run in the afternoon.

E) He has all his athletes repeat the 400m on different daysafter having one of the three drinks - on Monday they all haveGatorade, on Wednesday Powerade and on Friday Vitaminwater.

F) He has all his athletes repeat the 400m on different daysafter having each of the three drinks - and uses randomization todetermine which drink they have each day.

G) He creates groups of three similar athletes after rankingthem by speed, then randomly assigns one person from each group toget either Powerade, Gatorade,or Vitaminwater.