00:01
For this problem, we are asked, why do we square the deviation from the mean before adding them to compute the variance? so what we want to do, or the part of the reason, is that we want to avoid adding to zero, i .e., if we had the set negative 5 .05, and we didn't do anything to square or to eliminate the fact that we have negative deviations, then that would indicate that a type of variance would be zero.
00:41
If we just took the sum of the differences, which clearly that's not what we want.
00:47
Treating everything or treating all the differences as positive, so if we said, okay, well our differences, clearly here the mean would be zero, but we can see that the differences would be negative five plus positive five.
01:01
If we treated those as all absolute values, then that could work, that leads to problems outside the scope of the course.
01:11
But what we can do instead is square everything and then take the square root...