A researcher is interested in the relationship between number of hours spent studying for a test and the performance on the test. She wishes to use an experimental design, so she divides her participants into two groups. Group A studies for 15 min for a simple trivia test. Group B studies for 3 hours for the simple trivia test. Is this the best design for the study? Why or why not?

A researcher is interested in the effect of slightly elevated heart rate on participant's ability to perform two tasks simultaneously. The researcher has one group do mild exercise to increase their heart rate and has them listen to a story while performing a word find task. The other group performs the task at resting heart rate. Is this an appropriate design for the study? Why or why not?

A researcher is interested in whether the amount of sleep a person gets affects their cognitive functioning devises a study in which he has participants organized into three groups. The first group is allowed to sleep for their usual time. The second group sleeps for an hour less than their usual time. The third group sleeps an hour more than their usual time. He then observes each group throughout the day rating their cognitive sharpness. What kind of design is this? Is it the best design to answer this question? Why or why not?