(a) It is an observational study because the researchers are simply observing the results between
two different groups. To do an experiment, the researcher must manipulate the variable of
interest (different weight-loss programs) in order to compare their effects.
(b) Inform the volunteers that they are going to be enrolled in a weight-loss program and their
progress monitored. As they enroll, randomly assign them to one of two groups, say Group A and
Group B (without the subjects’ knowledge that there are really two different programs). Group A
gets one program and Group B the other. After a period of time, compare the average number of
pounds lost for the two programs.
- (a) There is a moderate to strong positive linear relationship between the scores on the first and
second tests.
(b) 0.78^2 = 0.61. About 61% of the variation in scores on the second test can be explained by the
regression on the scores from the first test.
marvins-underground-k-12
(Marvins-Underground-K-12)
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