00:02
Hello, we are given a discrete probability distribution and we have to calculate the variance and standard deviation for this distribution.
00:13
We are also given that the mean of the distribution is 5 .64.
00:19
Now the formula for the definition of variance is expected value of x minus the means the square of this thing expected value of this square.
00:30
Now this thing is also equal to expected value of x square minus expected value minus the square of the mean.
00:39
Now we are going to use this formula to calculate the variance.
00:44
Well, we are already given the expected value of well we are already given the mean.
00:49
So we need to find this.
00:52
Now to find this we add another row to this table of the square of the values.
00:58
So 2 we have 4, 4 we have 16, 5 we have 25, 8 we have 64, 9 we have 81.
01:05
And now we go forward to calculate the expected value of x square which is 4 times 2 by 11 plus 6 times 7 by 22 plus 25 times 1 by 11 plus 64 times 3 by 22 plus 81 times 3 by 11.
01:22
When we do this we get 428 by 11.
01:27
So this is the variance.
01:29
Sorry, this is the expected value of x square.
01:32
So the variance is 428 by 11 minus the square of the mean which is 5 .64 whole square...