00:01
Okay, we are told the heights follow a normal distribution.
00:04
So a fell shape curve like this.
00:07
The mean is 170.
00:08
It's in the middle every time.
00:10
So you have symmetry either side of the line or x equals 170.
00:16
And we're told sign deviation is 8.
00:20
Now with normal curves, there's this formula, or this theorem called the empirical formula, which is 68, 95, 99 .7.
00:33
And those three numbers relate to one sound deviation away from the mean, two sound deviations away from the mean, and three sd from the mean.
00:47
And these numbers represent the percentage of data that lies in the given range.
00:53
So for example here, if i do one sd away from the mean, the sd is eight and even variation is 8 from here...