Introduction to the Correlation Coefficient
Yesterday, you explored scatterplots and lines of best fit. Today, you will look at how strong the relationship is between two variables and learn about the correlation coefficient, which is written as r.
Putting It All Together
Answer these open ended questions on your own or with others to form deeper math connections.
What does it mean when ?
What does it mean when ?
In your own words, describe what a data set might look like if ?
If you are told a data set shows a linear relationship, what could you expect to see for the correlation coefficient ?
Guess the Correlation
What effect does and outlier have on the correlation coefficient? Move the red point around and see what effect this has on both the line of regression and r value.
Extension
Go back to the data we looked at yesterday. Which ones had the strongest linear relationship? Are there others where you could remove a data point or two and it would have a strong relationship?