This applet has two functions: plotting and finding the quadratic function 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 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. Errors 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.