Experimental Designs Answers

What type of experimental design did Betty use?

Use the diagram to identify the components of the completely randomized design.

✔ random assignment60 cookiesthe 4 temperaturesgroups of 15 cookiescomparison of “perfection” rating

random assignment60 cookiesthe 4 temperatures✔ groups of 15 cookiescomparison of “perfection” rating

random assignment60 cookies✔ the 4 temperaturesgroups of 15 cookiescomparison of “perfection” rating

random assignment60 cookiesthe 4 temperaturesgroups of 15 cookies✔ comparison of “perfection” rating

Use the design web to identify the components of the experiment.

✔ seniorsjuniorsnew techniquerandom assignment

seniorsjuniorsnew technique✔ random assignment

seniorsjuniors✔ new techniquerandom assignment

Version A✔ Version B

Betty wants to bake the perfect cookie. She wants to determine the ideal temperature at which to bake the cookies. She has enough batter to make 60 cookies. She decides to randomly assign 15 cookies to be baked at 300°, 15 at 325°, 15 at 350°, and 15 at 375°. The baking time for each batch is 12 minutes.Which statement about the randomization for the completely randomized design is correct?

A swim instructor would like to test the effect of a new swim technique versus the standard technique for a group of 25 competitive swimmers.The swim instructor divides the students by class (junior or senior), and then randomly allocates half of the 14 juniors and 5 of the 11 seniors to receive instruction on the new technique.During swim practice, the instructor times the juniors as they race against each other to see if those who learned the new technique outperform their peers. The instructor does the same for the seniors.At the end of practice, the instructor compares the average swim time for both juniors and seniors among those who did and did not use the new technique.What type of experimental design did the instructor use?

Which statement about the randomization for the block design is correct?

A nutritionist wanted to determine which of two behaviors would give people the most energy. She selected a sample of 50 adult participants.For one month, the participants were asked to exercise for 30 minutes per day. For another month, they drank an energy drink every day. The order of the treatments were assigned to the participants at random.The participants were asked to record each day when they completed their treatment and to rate their energy level that day on a scale of 1–10.After the two months of treatments, the nutritionist collected the data and calculated and compared the mean change (exercise – energy drink) in energy level for all 50 participants.What type of experimental design did the instructor use?

Which statement about the randomization for the matched pairs design is correct?

Use the design web to identify the components of the experiment.