00:01
In a sample of 3 ,000 students, the mean gpa is 2 .90 and the standard deviation of 0 .25.
00:06
Assuming that the distribution is set to be normal, what percent of students call between 2 .7 and 3 .0? so let's go into our worksheet.
00:16
Population mean mu is equal to 2 .90.
00:19
Population standard evasion sigma is equals to 0 .25.
00:25
N is actually cost 3 ,000.
00:27
And the probability that we have 2 .7 less than x less than 3 .0 so to get this probabilistic value over here we have to standardize each of this random variable that's 2 .7 and 3 .0 rather and to do so we have the formula that says z is equals to x minus mu divided by zima so our x in this case uh so let's start with 2 .7 at x having a value of 2 .7 we have a z to be equals to 2 .7 minus 2 .90 divided by 0 .25 so when we do the match with our calculator 2 .7 minus 2 .90 that gives us minus 0 .2 divided by 0 .25 we have our answer to be equal to minus 0 .8 and at x having a value of 3 .0 we have a z to be equals to 3 .0 minus 2 0 .90 divided by 0 .25.
01:37
So 3 minus 2 .90 that gives us 0 .1 divided by 0 .25.
01:43
So 0 .2.
01:44
So 0 .2 5 that gives us as 0 .4.
01:47
So we can rewrite our question as probability of minus 0 .8 less than z less than 0 .4.
01:55
So for better understanding and easily get to easily get our answer, we have to sketch...
