00:01
All right, so we have two things we want to answer here about the sat rate at a certain school.
00:07
The national average for percentage we take the sat is 49%.
00:12
195 out of 300.
00:14
Took it at this certain school.
00:16
We want to determine is there a difference between the school and the national average.
00:19
So this is a proportion test.
00:21
Our null hypothesis is that the proportion is the same as the national average of 0 .49.
00:27
And our alternative is that it's not.
00:30
It's just different from .49.
00:35
Now, we can find a p value here, but first we want to find the test statistic, which is going to be the z score.
00:42
And the form is in the box there, and actually before we do that, we need to compute p hat, which is the sample proportion, and this is x over n, or 195 over 300, which is 0 .65.
00:59
All right, so now, so we can compute .65 minus .49 divided by the square root of .49.
01:22
.51 over 300.
01:27
So this is going to be .16 over .089, which is 5 .54.
01:56
So now we can find the p value to make the determination.
02:02
So that's going to be, because the two -tailed test here, because of the not equals sign, this is going to be two times the probability z greater than 5 .54.
02:15
So that's going to be two times, this is going to be essentially zero.
02:20
It's going to be very small...