Jane is interested in whether regular aerobic exercise reduces cholesterol levels. To examine this question, Jane performs two studies:
Study A) Jane recruits 1000 participants for the study. When the participant arrives at the lab, they fill out a questionnaire indicating how many hours per week of aerobic exercise they do. They then have blood drawn to check their cholesterol levels.
Study B) Jane puts up fliers looking for participants who rarely exercise. 100 such individuals sign up for her study. All participants first have blood drawn to check their cholesterol levels. Then, Jane randomly assigns half of the participants to the "Aerobic Exercise" group - where the participants have to do 30 minutes of aerobic exercise, three times per week, for six months. The other half of the participants are assigned to the "Stretching" group - where the participants have to do 30 minutes of stretching without any aerobic activity, three times per week, for six months. Finally, after the six months are up, all participants have their blood drawn again to check their cholesterol.
In Study A, Jane finds that there is a correlation of -0.5 between hours of aerobic activity and cholesterol level. From this she can conclude that:
Harry and Omar are baseball pitchers who go to different high schools. They are both learning to throw three new types of pitch: curveball, slider, and changeup. At each practice, Harry's coach has Harry practice his pitches in order. Harry first throws 40 curveballs, then 40 sliders, and then 40 changeups. At each practice, Omar's coach also has Omar throw 40 of each type of pitch, but he tells Omar to practice the different pitch types in a random order.
When the two boys are asked to rate how effective they think their practice has been, _________ will give the highest ratings. When the two boys' performance is actually measured (e.g., by examining their effectiveness in games), ________ will show the best performance because his practice has been more _________.
Infants and children will naturally cry when they are in pain. When Debbie takes her child to the doctor's office to get his first vaccination shot, the child shows no response to the doctor's office. After getting the shot though, the child cries. Three months later, when Debbie brings the child back for another vaccination, the child does not respond to the doctor's office, but again, after getting the shot, the child cries. Six months later, as soon as Debbie and her child enter the doctor's office, the child begins to cry.
In the scenario above, the child crying in response to the pain from getting a shot would be considered the:
Marquis is a piano teacher. On Monday he asked five of his students to practice a brand-new musical piece for 5 total hours over the coming week and to keep a journal of their practice. That Sunday, Marquis collected the student's journals. Marquis noticed that all five students had practiced for exactly 5 hours as he had asked, but they did so in different ways:
Student #1: Practiced for 5 hours on Saturday Student #2: Practiced for 2 ½ hours on Tuesday and 2 ½ hours on ThursdayStudent #3: Practiced for 2 hours on Tuesday, 2 hours on Thursday, and 1 hour on SaturdayStudent #4: Practiced for 2 hours on Tuesday, 1 ½ hours on Thursday, and 1 ½ hours on SaturdayStudent #5: Practiced for 1 hour on Tuesday, 1 hour on Wednesday, 1 hour on Thursday, 1 hour on Friday, and 1 hour on Saturday
All other things being equal, which student would Marquis expect to have best learned the piece?