00:02
In this problem, we are given some data.
00:10
We have x's and y's.
00:15
And first we're going to draw a scatter diagram of the data.
00:21
And to do that, we will look at each of these x and y's as a coordinate pair.
00:28
So we can think of this as x, y, and the first coordinate pair will be 0 and 3.
00:34
So we'll come here to 0 and come up to 3.
00:42
That will be our first point.
00:47
And then our next coordinate pair will be 5 .8.
00:54
5 and go up to 8.
00:58
So that should be right here.
01:06
1 .6.
01:08
So that will be 7.
01:11
And then come up to 6, which is right here.
01:18
Our next coordinate pair will be 8, 9.
01:21
So we come over to 8.
01:24
We'll go up to 9, which is right here.
01:31
And then our final coordinate pair will be 9, 4.
01:35
So let's go to 9 and then up to 4.
01:40
So right here, it's our last coordinate pair.
01:48
All right, so we've plotted the scatter diagram.
01:55
Just looking at the scatter diagram, it does not appear that there's a linear relationship here.
02:01
It sort of did until we added this point, but once we added that point, this sort of looks random.
02:11
It doesn't look like there's a linear relationship.
02:14
But let's go ahead and calculate r.
02:16
So what i like to do for my step two is to make this table where i have my x's, my y's, and then we calculate our x squared, it's, and then the product of x and y.
02:34
And the reason for that, is because it will make the calculation of r in this big formula much easier.
02:42
So first, let's just write down what our x's are.
02:46
0, 5, 7, 8, 9.
02:52
Our ys are 3, 8, 6, 9.
02:59
I'm just copying that from what we're given.
03:04
In the next column, we're going to compute the x squared values.
03:11
We're going to take each x and square it.
03:14
So we'll start with zero.
03:15
So zero squared is just zero.
03:20
Then five squared is 25.
03:24
Then seven squared is 49.
03:28
Then eight squared is 64.
03:32
And then nine squared is 81.
03:35
In the next column, we will do the same thing, but for the y's.
03:41
So we'll look at the first y, which is three.
03:44
We'll square it.
03:46
3 squared is 9.
03:49
8 squared is 64.
03:53
6 squared is 36.
03:57
9 squared is 81.
04:00
And 4 squared is 16.
04:04
And then for our last column, we will compute the product of x and y, for each coordinate pair.
04:12
So we'll start with the first row, which will be 0 times 3.
04:18
So 0 times 3 is 0.
04:22
Then move on to 5 times 8, which is 40...