00:01
So this problem would actually be a binomial setting, and we have the probability of resolving being 75%, and we have 13 different cases being looked at.
00:11
And we're going to let x stand for the number of cases that are resolved.
00:16
And we know we have a 75 % chance in each one.
00:18
We are going to assume that each one is independent.
00:21
So we want the expected value to begin with.
00:25
And that expected value is n times p.
00:27
So we're going to take that 13 times .75, and 13 times .75, or three quarters of that, comes out to be 9 .75.
00:38
Now we want to know what the standard deviation is, and that's going to be the square root of n times p times 1 minus p, which will be that square root of 13 times .75 times .25.
00:53
So we can take that answer that we just got times .25 and then square root that answer.
00:59
And that comes out to, i don't know if it said two or four, that's to two decimal places, to four decimal places is 1 .5612.
01:08
So depending on which one you need.
01:11
Next, you want to find what is the probability of having exactly 10.
01:15
Now, that is a binomial setting.
01:17
So it's technically that combination of 13 choose 10 times 0 .75 to the 10th power.
01:23
And 0 .25 to the third power.
01:26
Now i'm going to use my binomial pdf for this and getting under second and distribution.
01:35
And that is a probability density function, and we're going to use 13 trials, and we're going to use the probability of success of 0 .75.
01:45
And we want that value to be 10...