00:01
Here we have the probability distribution for the number of accidents at a job over the month.
00:08
And we are asked to compute the mean, the variance, and the standard deviation on the number of accidents.
00:15
Now the mean is given by this formula.
00:18
It's the summation of x times the probability of x.
00:23
And here x is the number of accidents in the month.
00:29
So this is 0 times 0 .4 plus 1 times 0 .2 plus 2 times 0 .2 plus 3 times 0 .1 plus 4 times 0 .1.
00:43
And that comes out to 1 .3.
00:47
And the variance for distribution is given by this formula.
01:00
And let's use excel to help calculate this.
01:04
First, we will calculate x minus mu for each value of x.
01:10
Then we will find the square of that.
01:12
And then we will find the product of that with the probability.
01:16
And finally, we will sum them to find our variance...