0:00:00.000,0:00:05.000
And obviously the new mean is 1.2 times the old mean because we're multiplying
0:00:05.000,0:00:11.000
everything up by 20% raise that makes a factor of 1.2 over here and zero over here
0:00:11.000,0:00:15.000
because we don't really add a constant amount of money per person its variable.
0:00:15.000,0:00:19.000
It's a multiplicative change. For the variance it's more interesting.
0:00:19.000,0:00:27.000
In our new variance, we multiply each salary by a factor of 1.2 and the same is through for the mean.
0:00:27.000,0:00:34.000
When we look at this, we can bring the 1.2 outside these brackets and it becomes (1.2)².
0:00:34.000,0:00:40.000
The reason why I squared this, we can bring it outside Xi and u but there's a square over here
0:00:40.000,0:00:42.000
and we can move it outside this sum as a factor.
0:00:42.000,0:00:45.000
Now this is true for the variance but not the standard deviation.
0:00:45.000,0:00:48.000
The standard deviation is cleared of the variance.
0:00:48.000,0:00:55.821
The standard deviation was up by factor of 1.2 only, with a constant offset of zero.