1
00:00:00,000 --> 00:00:03,000
Y will always be less extreme.
2
00:00:03,000 --> 00:00:08,000
The key to understanding this simply is this equation.
3
00:00:08,000 --> 00:00:18,000
This is what tells us that the standard scores have a regression coefficient â¤ 1.
4
00:00:18,000 --> 00:00:25,000
We said it's 1, and so because it's not 1 it must be less than that.
5
00:00:25,000 --> 00:00:28,000
That means the standard score shrinks.
6
00:00:28,000 --> 00:00:35,000
If the standard score shrinks that means if it's negative it moves this way.
7
00:00:35,000 --> 00:00:37,000
If it's positive it moves this way.
8
00:00:37,000 --> 00:00:40,000
That means there is more area under here,
9
00:00:40,000 --> 00:00:45,000
so this has to be a little more area than this.
10
00:00:45,000 --> 00:00:49,000
Therefore, y will always be less extreme.
11
00:00:49,000 --> 00:00:51,000
This is the concept of regression.
12
00:00:51,000 --> 00:00:55,000
That is regression to the mean.
13
00:00:55,000 --> 00:00:58,000
If someone is exceptional in one thing,
14
00:00:58,000 --> 00:01:02,000
we will always predict that person to be a bit less exceptional
15
00:01:02,000 --> 00:01:07,000
in that other thing if there is any error.