1
00:00:00,000 --> 00:00:05,000
And obviously the new mean is 1.2 times the old mean because we're multiplying
2
00:00:05,000 --> 00:00:11,000
everything up by 20% raise that makes a factor of 1.2 over here and zero over here
3
00:00:11,000 --> 00:00:15,000
because we don't really add a constant amount of money per person its variable.
4
00:00:15,000 --> 00:00:19,000
It's a multiplicative change. For the variance it's more interesting.
5
00:00:19,000 --> 00:00:27,000
In our new variance, we multiply each salary by a factor of 1.2 and the same is through for the mean.
6
00:00:27,000 --> 00:00:34,000
When we look at this, we can bring the 1.2 outside these brackets and it becomes (1.2)².
7
00:00:34,000 --> 00:00:40,000
The reason why I squared this, we can bring it outside Xi and u but there's a square over here
8
00:00:40,000 --> 00:00:42,000
and we can move it outside this sum as a factor.
9
00:00:42,000 --> 00:00:45,000
Now this is true for the variance but not the standard deviation.
10
00:00:45,000 --> 00:00:48,000
The standard deviation is cleared of the variance.
11
00:00:48,000 --> 99:59:59,999
The standard deviation was up by factor of 1.2 only, with a constant offset of zero.