00:01
In number seven, we're asked to construct a 90 % confidence interval using data from 10 .2, number seven.
00:08
And it's not really data.
00:09
You're actually given summary statistics.
00:11
So you're given the summations of the x's and the ys and the x squared and the y squares and the y squares and whatnot.
00:16
So we actually have to use the formula here.
00:17
So beta 1 hat, this is the confidence interval.
00:19
It's beta 1 hat to the point estimate plus or minus.
00:23
This is the margin of error.
00:24
So t alpha over 2 is the critical value.
00:27
So, se is the square root of sse over n minus 2, and then divided by the square rate of ssx.
00:34
Now, fortunately, we found some of this already.
00:36
The beta 1 had is 0 .6.
00:39
We found that in a previous problem.
00:42
Ssxx, we found that in the previous problem as 40.
00:46
So the rest of this stuff, we need to kind of work through.
00:52
So let's find the sse first, because once we find the sse, then we can find the se.
00:57
So sse is the s -syy minus beta 1 hat times ssxy.
01:04
And we actually found all this stuff too.
01:06
So ssy -y -y is 18 .8.
01:08
We found that in a previous problem.
01:11
Beta -1 hat is .6.
01:12
We found that in a previous problem.
01:14
And then the ssxy is 24.
01:17
We found that in a previous problem.
01:19
So whenever you do that, you should get 4 .4.
01:21
So now, once we do that, we can find the se.
01:25
So that's the square root of s -s -s -e.
01:27
Which is 4 .4 divided by the degrees of freedom, which is n minus 2.
01:33
And the sample size here was five, so we're dividing that by three.
01:40
And whenever you do that, you should get the sse.
01:44
In all honesty, i'm not 100 % sure what it is because i just have it...