00:01
So for this problem, we're trying to find our regression equation, the form of y hat equals intercept, beta, not, plus slope, beta, 1, times x.
00:12
Our slope, beta 1, is equal to ssx, or, pardon me, no, it's ssxy, divided by ssxx, and beta not is equal to y bar minus beta 1 times x bar.
00:31
Now, sxy is equal to the sum of the product between each paired x and y value minus 1 over n times the sum of each x value times the sum of each y value.
00:51
And ss xx is going to be equal to the sum of x squared minus 1 over n times the sum of x to the power of 2.
01:03
So to do this, i'm going to set up a table of values where i have x, y, and x squared, and i'm going to try to find what the total of x is, what the total of y is, and what the total of x squared is.
01:20
Now, i'm actually going to do this using xl, just for expediency here.
01:26
So we have our x's and our y's.
01:29
You can add these up by hand, of course, but i'm just using xl to make this quick.
01:35
So we have our sum of all of our x values and the sum of all the y values.
01:42
And for x squared, well, we simply be taking each x value and squaring it.
01:50
So we can see all of our x squareds.
01:57
And why am i not? there we go.
02:00
We can see that the number of observations is equal to seven.
02:04
So we'll take note of that as well.
02:07
So grabbing those, or really what we're concerned with is going to be the totals back in here.
02:18
We can find our ssxy by, well, plugging in all of the data that we have, except for the fact i'm missing one thing that i needed to calculate, which would have been the x times y's, pardon me.
02:33
So we just multiply each x and y value, so we do 1 times 8 and 2 times 6 would be 12 and so on.
02:41
So we have all of our x times y's.
02:44
And now we have, all of the data that we need...