00:01
All right.
00:02
So we're looking at a university that wanted to look at the number of beers of student drank and their bac blood alcohol content.
00:13
And they selected randomly 18 students.
00:17
And each student was randomly assigned some number of beers to drink.
00:22
And 30 minutes later, they consumed three minutes after they drank their beers.
00:27
The member of the sheriff's office took their bac.
00:31
And this is the data.
00:33
Along with some calculations that we'll get to in a moment.
00:37
That's what we get.
00:38
So name and beers and bac.
00:40
So the first thing we have to do is make a scatter diagram, and that's what we have here.
00:46
There we go.
00:47
And if we're looking at it, we can see it's going up and to the right, so it's positive, you know, positively correlated.
00:54
It's kind of cloudy, so moderately to strong correlation because you can still pretty easily see the trend.
01:04
And the correlation coefficient, those are the values that just erased.
01:07
Here but i'll show you what those are and how we get them.
01:11
So we need the mean and the standard deviation of the x is and the y's.
01:18
It's the sample standard deviation.
01:22
The sample of the population.
01:30
Get that.
01:32
Copy.
01:34
Those formulas are over.
01:36
So we still are referring to the cells right above it.
01:38
So it's good.
01:40
Then we do x minus x bar, y minus y bar.
01:45
And then we take the product of those and then we're going to sum those products so equals x equals six for that cell minus the mean lock it with the dollar signs same thing with the ys minus that lock it in the product copy and paste those down the beauty of spreadsheets good and then we're going to take the sum of all these products.
02:27
Then to get the r value, i'm going to put it up here, so we're going to use it.
02:32
You take the sum and we have the products and we divide it by n minus 1, which is 17 times the standard deviations...