00:01
Okay, so an investigator hypothesises that lack of regular exercises is associated with obesity.
00:08
And then he takes a sample of n equals 12 children and couldn't find any association in these 12 children between exercise habits and obesity.
00:22
And then it says this finding is likely a reflection of which are the following.
00:25
It's likely a section of option d, random error.
00:31
And i could tell you why, but question b sort of explains it.
00:36
On question b, the reason is the first one.
00:40
So it's an example of random error because the sample size is so small that we've just happened to get a group of people for which the correlation isn't there.
00:50
And a small sample size can lead to lower power, and that might have led to a type 2 error.
00:56
So remember, in this case, our null hypothesis would be that exercise is independent of obesity.
01:07
And the alternative hypothesis would be that it's dependent, exercise is dependent on obesity, or the other way around actually really, obesity is dependent on exercise.
01:19
That you should be the other way around...