00:01
Okay, so we got our x independent variable and our y dependent variable.
00:08
They tell us the correlation coefficient is 0 .5098.
00:13
Well, 0 .5098 is going to mean that it is positive, that's because the number is positive.
00:24
And it's going to have a moderate, it's going to have a moderate, relationship, because our correlation goes from negative 1 to 1, and 0 is the weakest.
00:54
So 0 .5 is right in the middle of like a moderate to strong linear relationship in the positive direction.
01:08
Okay, so now i'm going to show you two ways to find the slope the y intercept in excel, and that's because i'm not sure how you're going to be calculating or what you're going to have to use.
01:21
So this formula says it's for b.
01:25
That's for the slope.
01:27
And this one, for a, is for the y intersect.
01:33
Okay.
01:38
So i'm going to use these formulas first to find it.
01:42
So we would find the mean because.
01:45
Actually, let's start with standard deviation.
01:47
To find the slope, we need the standard deviations and the correlation.
01:53
And in order to find the y intercept, we need the slope.
01:57
So this is the standard deviation of y and the standard deviation of x.
02:01
So let's find the standard deviation of x and y.
02:04
So in excel, you type in st, and then you pick the one that says dot s, and then you select your column.
02:16
So let's do that one more time.
02:18
St .s, because it's a sample, and then hit enter.
02:25
So those of our standard deviation.
02:28
So now i can find my slope.
02:30
My slope is the correlation.
02:33
Primes, you have to make sure you put in the times or it doesn't know what to do.
02:37
Standard deviation of y divided by standard deviation of x.
02:43
My slope is 0 .810119.
02:48
Now, for our y intercept, we're going to need the mean of x and mean of y.
02:54
And that's because the mean of x, mean of y point is always on the least squared regression line every single time.
03:07
Now, to find the mean, add them up, divide by five.
03:11
Or in excel, you just type in average and then highlight the data.
03:18
All right.
03:19
So let's find our y intercept.
03:21
So it's going to equal the mean of y minus the slope times the mean of x.
03:33
So our y intercept is going to be 9 .3145.
03:39
Now, i can do that.
03:41
If i'm in excel, i can just tell it to find me the least square regression line.
03:46
You type in l -i -n and you pick this one that says e -s -t.
03:52
And then it tells you what to put in.
03:54
So this is how it works...