00:01
What's up, stackcats? in this video, we're going to be discussing an experiment in some of the aspects of the design.
00:06
So recently, a group of adults who swim regularly for exercise were evaluated for depression.
00:12
It turned out that these swimmers were less likely to be depressed than the general population.
00:17
The researchers said the difference was statistically significant.
00:21
Okay, so the researchers identified swimmers and asked them if they were depressed or not, and did the same with the general population.
00:30
So what does statistical significance mean in this case? so the researchers are basically saying because these people are swimmers, that makes them less depressed.
00:45
So the impact of swimming is not attributable to sampling variation.
00:54
So because they swim, that makes them less depressed.
01:10
Okay, so part b wants to know, is this an experiment or an observational study? so they didn't really give us a lot of details, but we do know that there was no randomization, so that automatically makes it not an experiment.
01:28
And then if we just think about it otherwise, they're identifying people who already swim and asking them if they're depressed or not.
01:37
So this is observational.
01:51
Okay, part c is news reports claimed this study proved that swimming can prevent depression.
01:59
Explain why this conclusion is not justified by the study.
02:04
Include an example of a possible lurking variable.
02:08
So a lurking variable is a variable that has impact on the relationship among our other variables.
02:16
Variables but is not one of our independent variables.
02:22
So it could be that the people that were swimmers already had healthy lifestyles otherwise that somehow also a tribute to them being less depressed.
02:44
So like an example of a lurk of a lurk, variable would be in that like in the sense of what i just said like previous lifestyle i guess we could call it previous lifestyle maybe age maybe these swimmers just happen to be in an age group that experiences differential rates of depression so that's why i think that that claim is not justified by the study...