About this video
Aubrey wants to know whether the period of the day an exam happens affects the average score. The video puts Period on the horizontal axis and average score on the vertical axis, plots each class as a point, and finds no obvious trend.
You'll be able to
- decide which variable goes on the horizontal axis and which on the vertical axis.
- plot data from a table as points on a scatter plot.
- look at a scatter plot and say whether there is an obvious trend.
Key words
- scatter plot
- A graph that shows pairs of data as dots so you can look for a connection.
- horizontal axis
- The left-to-right axis; it shows the variable that might be driving the other one.
- vertical axis
- The up-and-down axis; it shows the variable that is being driven.
- trend
- A general pattern in the dots, like going up or down together.
- correlation
- A connection where two variables tend to change together.
Transcript
Aubrey wanted to see if there's a connection between the time a given exam takes place and the average score of this exam. She collected data about exams from the previous year. Plot the data in a scatter plot. And let's see, they give us a couple of rows here.
This is the class. Then they give us the period of the day that the class happened. And then they give us the average score on an exam. And we have to be a little careful with the study-- maybe there's some correlation depending on what subject is taught during what period.
But let's just use her data, at least, just based on her data, see if-- well, definitely do what they're asking us, plot a scatter plot, and then see if there is any connection. So let's see. On the horizontal axis, we have Period. And on this investigation, this exploration she's doing, she's trying to see, well, does the period of the day somehow drive average score?
So that's why Period is on the horizontal axis. And the thing that's driving is on the horizontal, the thing that's being driven is on the vertical. So let's plot each of these points. Period 1, average score 93-- right over there. Period 6, 87. Oh, that's not the right place, and then we can move it if we want-- 87, right over there.
Period 2, 70. Period 4, 62-- right over there. Period 4 and 86, that's right over there. Period 1, 73. Period 3, average score of 73 as well. Period 1, 80, average score of 80. And then Period 3, average score of 96. So there we go. And it doesn't really seem like there's any obvious trend over here.
So let's make sure that we got this right. And we did.
Video © Khan Academy, used under CC BY-NC-SA. Watch on Khan Academy. Puzzicle is not affiliated with Khan Academy.