Introduction
R-squared, denoted as R^2, is a statistical measure that represents the proportion of the variance in a dependent variable that can be explained by an independent variable in a regression model. It is a crucial metric for assessing the goodness of fit of a regression model. To make this calculation easier, we’ll guide you through creating an HTML R-squared calculator, complete with the Sum of Squares of the Residuals (SSR), Total Sum of Squares (SST), and the R-squared value (R^2).
How to Use the R-Squared Calculator
To use the R-squared calculator, follow these steps:
- Enter your observed and predicted values into the calculator.
- Click the “Calculate R^2” button.
- The calculator will then compute the R-squared value based on the provided data.
Formula
The formula for calculating R-squared (R^2) is:
R^2 = 1 – (SSR/SST)
Where:
- R^2 is the R-squared value.
- SSR represents the Sum of Squares of the Residuals.
- SST represents the Total Sum of Squares.
Example
Let’s work through a simple example to calculate R-squared using the given formula.
Suppose you have the following data:
Observed Values: [10, 15, 20, 25, 30] Predicted Values: [12, 14, 18, 22, 28]
First, calculate SSR and SST:
- SSR = Σ(yi – ŷi)^2 = (10-12)^2 + (15-14)^2 + (20-18)^2 + (25-22)^2 + (30-28)^2 = 10
- SST = Σ(yi – ȳ)^2 = (10-21)^2 + (15-21)^2 + (20-21)^2 + (25-21)^2 + (30-21)^2 = 90
Now, plug these values into the R-squared formula:
R^2 = 1 – (SSR/SST) = 1 – (10/90) = 1 – 0.1111 = 0.8889
So, the R-squared value for this example is approximately 0.8889.
Frequently Asked Questions (FAQs)
1. What does R-squared (R^2) measure?
R-squared measures the proportion of the variance in a dependent variable that can be explained by an independent variable in a regression model. It quantifies the goodness of fit of the model.
2. What does SSR stand for in the R-squared formula?
SSR stands for Sum of Squares of the Residuals. It represents the sum of the squared differences between the observed and predicted values in a regression model.
3. Can I use this R-squared calculator for multiple regression?
Yes, you can use this calculator for multiple regression by entering the observed and predicted values for each data point.
4. How can I implement this R-squared calculator in my website?
You can implement this calculator by embedding the HTML code provided in your website’s code, along with the necessary JavaScript in a <script> tag.
Conclusion
Calculating R-squared (R^2) is essential in regression analysis to assess how well a model fits the data. By creating an HTML R-squared calculator with the formula R^2 = 1 – (SSR/SST), you can easily determine the goodness of fit of your regression models. Use the provided code to integrate this calculator into your website, making it accessible to users with a convenient clickable button.