00:01
Okay, so i see that you need help with this question, and it says the out -of -state tuition and dollars for random samples of both public and private four -year colleges in new england state are listed.
00:11
Find the 95 % confidence interval for the difference in the means.
00:16
Assume the variables are normally distributed and the variances are equal.
00:20
Round the sample statistics and final answers to two decimal places.
00:27
So let me just get rid of this on the side, so that way i have some more room.
00:36
And for this, the first thing for the public, the mean is going to be 1576 .6, and the standard deviation is going to be 3385 .94.
00:56
And for private, the mean is going to be 10199 .14, and the sample standard deviation is going to be 4698 .88, okay? and the sample size for private is 10, and for public is seven.
01:30
And so the first thing that i have to do is i have to pull their variances.
01:37
So i have to take the degrees of freedom for the private is nine, and for the public is eight.
01:46
So i'm going to take nine times 4698 .88 squared plus, oh, i don't know why i put eight there.
02:04
That should be six.
02:05
Ooh, that should be six.
02:15
So six times 3385 .94 squared, and that is divided by 10 plus seven minus two, and that equals 15710531 .02.
02:35
And so you're gonna take this number, and you're gonna find the square root of that, and that's going to equal 3963 .65...