A few years? ago, a certain company introduced a line of? new,slick swimsuits. Some say that they gave the wearers an advantagein races. In order to test whether the suits were? effective,suppose that there are 80 swimmers;40 of them are?professional-level swimmers, and 40 are? amateur-level swimmers.The designers will ask the swimmers to swim 200metres as fast aspossible. It is reasonable to assume that the effects of the suits?(due to dynamic forces of the? water) might be different for thetwo levels of swimmers.

Describe a simple randomized design? (not blocked) to testwhether the slick suits decrease race times. Explain how to assignthe swimmers to treatment groups. Choose the correct answerbelow.

A.Have each simmer wear a slick suit for a 200?-metre race.Record each? swimmer's time. Ask each swimmer if this timedecreased from his or her normal 200?-metre

time.

B.Randomly assign each swimmer to wear either a slick or a?non-slick suit. Place in a bag 40 tickets that say? "slick" and 40that say? "non-slick." Have each swimmer choose a ticket and usethat type of suit in a 200?-metre race. Record each? swimmer'stime.

C.Randomly assign a type of suit to each level of swimmers.Place 2 tickets in a? bag, one that says? "slick" and one thatsays? "non-slick." Pick one? ticket, and assign that type of suitto the professional swimmers and the other type of suit to theamateur swimmers. Have them swim a 200?-metre race. Recordeach?swimmer's time.

D.Let each swimmer choose whether they want to wear a slick suitor a? non-slick suit, and then have them swim a 200?-metre race.Record each? swimmer's time.