00:01
In question 13, it's explained that normally when we do these paired sample tests, we find the mean of the differences between x1 and x2 by subtracting x2 from x1.
00:18
But they suggest that we could also, instead, just find the means of each x1 and x2 and then subtract the means.
00:28
Basically what the question is saying is normal procedure is we take x1 and we subtract x2.
00:36
And we do this for each sample pair.
00:41
And then we average these differences to arrive at the average of the differences.
00:53
So basically this is our value for mean difference.
01:01
And now they're suggesting that what we could do instead is simply take all the x1 values.
01:10
So this is sort of the before, the before values for the sample pair.
01:17
Average those to find the x1 average, and then do the same thing for x2.
01:28
Average those and get x2 average, and then take the average of x1 and subtract the average of x2...