00:01
The following is a solution to number three.
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We're given a data set.
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Here are the x values, 1, 4, 4, 4, 6, and 8.
00:05
And then the corresponding y values 4, 1, negative 1, and 0.
00:10
And for part a, we're supposed to draw the scatter plot.
00:12
And you can do that manually with the normal cartesian plane, or you can use any sort of technology you so wish.
00:18
And i'm going to use a technology.
00:19
I'm going to use a ti84, because it works out pretty nicely.
00:21
So if you go to stat on a ti84 and press edit, and l1 is where you're going to put your x values, and then l2 is going to be where you put.
00:30
Putting y values so 1 3 4 6 and 8 for the x and l1 and then 4 1 3 and negative 1 and then 0 for y and l2 then if you go to second y equals you go to that stat plot just make sure this first stat plot i like the first one and then the other ones are turned off so plot 1 is on so just make sure this is highlighted as for type it should be the scatter plots of this first graph here x list is l1 and y list is l2 unless you put it in different columns and then as for the mark you do any one of these that you want.
01:01
I like this first one because it shows up pretty nicely.
01:03
Then if you press graph, you can see the data values.
01:06
So there are the five points that we were given.
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Now, if you don't see them, that's fine.
01:09
If you just go to zoom and then this ninth option zoom stat, then you should see what you're seeing on your screen now.
01:16
So these are the five points, and that's, you know, what you'd either print out or draw out.
01:23
So that's the first part.
01:24
And then we're supposed to predict the sign of r.
01:27
And if you go back to that scatter plot and draw an imaginary line that kind of goes in between all these points, the slope of that line will be negative, and that tells you what the sign of r is going to be.
01:38
It's going to be negative.
01:40
Also, as x is increasing, y is decreasing.
01:42
So if you go back to these data values, as the x increases, the y seems to be getting smaller and smaller.
01:49
So i'm going to say the prediction for the sign of r here is going to be negative.
01:56
Okay, negative for a lot of things...