**QUADRATIC REGRESSION APPLET**

Scroll beyond the applet to see instructions and explanations

This applet has two functions: plotting and finding the quadratic function (of the form ) which best approximates the user supplied data. Use it as follows:

- Put the data to plot and analyze in the Data section. Though the variables
default to x (the independent variable) and y (the dependent variable), they
can be renamed. Renaming them will cause the graph to be updated. The values
are entered one per line. The data can be integers as well as real numbers. Scientific notation is allowed (for ex. 2.1E3 for 2100 or 2.1E-3 for 0.0021). You can also copy and paste data from any other application using the keys
to copy and*CTRL C*to paste.**CTRL V** - The buttons work as follows:
**CLEAR**will clear the data, the plot area and the RESULTS area.**PLOT**will plot the data as points.**ANALYZE**will find the quadratic function which best approximates the data, plot it and display its equation in the RESULTS area. - The plot area (top, right) will show the plot.
- The RESULTS area is used to communicate with the user.
- Error messages will be displayed there, for example if the number of values is not the same for both variables.
- Information will also be displayed there. For example, when the user clicks
on
**ANALYZE**, the equation of the regression function will appear there, as well as the error associated with this function and the correlation coefficient. The error is obtained with the formula where y denotes the y-values of the data points to fit and denotes the computed y-values. - The number of digits after the decimal point can be changed. Simply clicked on the button between "RESULTS" and "precision".

*This applet was developed by Dr. Philippe
B. Laval, at Kennesaw State
University.*

*This work was funded in part by:
*

The US Department of Education FIPSE #P116B00178