Line of Best Fit: y=- x+11 Correlation Coefficient: r=-0.444 Interpretation: A moderate, negative correlation
Practice makes perfect
We have been given a table with data for x and y.
x
5
6
7
8
9
10
11
12
y
12
- 2
8
3
- 1
- 4
6
0
In order to find a line of fit using our calculator, we need to first enter the values. Let's press the STAT button.
Then we choose the first option in the menu, Edit, and fill in the values in lists L1 and L2.
We can perform a regression analysis on the data by pressing the STAT button again, followed by using the right-arrow key to select the CALC menu.
This menu lists the various regressions that are available. If we choose the fourth option in the menu LinReg(ax+b) and press ENTER, the calculator performs a linear regression using the data that was entered.
We can round the value of b and substitute it along with a into the equation y= ax+ b. This gives us the equation for the line of best fit.
y= -1 x+ 11 ⇔ y=- x+11
We can see how the line fits with the data by plotting the data points and graphing the line on the same coordinate plane.
The calculator output gives us the value of the correlation coefficient, r.
r=-0.4435≈-0.444
This tells us that correlation is both negative and moderate. We can tell that it is moderate because it is around -0.5, which is a halfway between a direct correlation and no correlation.
