FSR - Correlation Lesson
Correlation
Introduction
To be able to effectively plan, you might need to make some predictions. What will the economy look like in ten years? How will inflation affect the worth of your house? Predictions can be made by looking at past data and searching for trends. If the trends continue, then you have a great model to predict what will happen in the future!
Correlation Activity
Click on the pink dots in the following activity to learn more about r- values, and correlation. Be sure to summarize the main points and add them to your notes!
Linear Regression Review
Let’s review how to find a regression line. Watch the following video and work along with the example shown.
Steps Using Your Calculator
*These steps may vary depending on your calculator.
Press STAT and then Edit.
Input the data.
Press STAT, then CALC, then LinReg, and ENTER
Steps Using a Spreadsheet
Input the data into two columns.
Highlight the data, click INSERT, and choose a scatterplot.
Using the design tools, change the layout of the scatterplot to include the trend line.
Correlation vs. Causation
It’s important to know that correlation, or a connection between two things does not always imply causation or the act of causing something. To determine whether or not one variable causes the other one to increase (or decrease) you must have a correlation but also be able to prove that one variable occurs before the other one. The independent variable should be causing the dependent variable to move in a certain way. This can typically only be proved by conducting research experiments. You also have to be able to rule out other potential causes.
Let’s say that there has been a positive correlation found between ice cream sales and lifeguard rescues. As sales of ice cream increase, the need for lifeguard rescues increases as well. But are the ice cream sales causing more lifeguard rescues? If this were the case, the lifeguard might try to ban ice cream on the beach. They’d probably find that it really wouldn’t change things though. Can you think of a variable that might connect these two that causes the correlation?
If you said the heat, or the sun, then you’d be correct! The ice cream sales aren’t causing more lifeguard rescues but rather the increase in the heat is causing both ice cream and lifeguard rescues to increase.
Correlation Practice
Drag the r-values to the correct gray box.
IMAGES CREATED BY GAVS