The Linear Regression Calculator can be used to derive the linear regression equation. Example is included to demonstrate how to use the calculator.
Please enter your values in the Calculator. Each value should be separated by a comma.
How to use the Linear Regression Calculator
Let's now review a simple example to see how to use the Linear Regression Calculator. Suppose that you have the following dataset:
- The X values are: 2, 7, 12
- The Y values are: 4, 11, 15
Plug the above values in the calculator. Each value should be separated by a comma:
Once you're done entering the numbers, click on the Get Linear Regression Equation button, and you'll see the Linear Regression equation, as well as the R-squared and the Adjusted R-squared:
How to Manually Derive the Linear Regression Equation
The equation of a Simple Linear Regression is:
Y = a + bX
Where:
- Y = Dependent variable
- a = Y-Intercept
- b = Slope of the regression line
- X = Independent variable
Let's now review an example to demonstrate how to derive the Linear Regression equation for the following data:
- The X values are: 2, 7, 12
- The Y values are: 4, 11, 15
To start, use the following equation to get the Y-Intercept:
(Σy)*(Σx2) - (Σx)*(Σxy) a = n*(Σx2) - (Σx)2
For our example:
- Σy = 4+11+15 = 30
- Σx2 = (22) + (72) + (122) = 197
- Σx = 2+7+12 = 21
- Σxy = (2*4) + (7*11) + (12*15) = 265
- n = 3
Plug the above results in the equation to get the Y-Intercept:
(Σy)*(Σx2) - (Σx)*(Σxy) (30)*(197) - (21)*(265) a = n*(Σx2) - (Σx)2 = 3*(197) - (21)2 = 2.3
So the Y-Intercept is 2.3.
Now let's get the Slope of the regression line using this equation:
n*(Σxy) - (Σx)*(Σy) b = n*(Σx2) - (Σx)2
Plug the values into the equation:
n*(Σxy) - (Σx)*(Σy) 3*(265) - (21)*(30) b = n*(Σx2) - (Σx)2 = 3*(197) - (21)2 = 1.1
You'll then get the slope of 1.1.
For the final part, let's construct the Linear Regression equation:
Y = a + bX = 2.3 + 1.1X