00:01
Okay, the mean is 12 and the variance is 3, 4, x.
00:10
And here what i'm doing is i'm adding 5, so x plus 5 and then i'm multiplied by 2.
00:18
So you add 5 first, then times by 2, so i end up with 2x plus 10.
00:29
Now i want to work out the new mean and new variance for 2x plus 10.
00:35
And it's a simple formula here.
00:45
If i have e of x is the mean.
00:52
Expect the value of x, same thing as the mean or the average.
00:57
If i have e of a x plus b, that i can write as e of ax plus e of b.
01:13
And this becomes a times e of x plus b.
01:22
If i have b is fixed, then the average of b plus b plus b plus b is simply b...