Statistical investigations are often interested in changes in a variable over time, or relationships among several variables. This applet describes straight-line relationships between two variables using the methods of correlation & regression.
The applet is organized as five "tabbed" display screens. The Data Sets tab lists textbook data sets to select. When the Data tab is selected data set values may be edited. Click the trash to clear all current values. The Correlation & Regression tab provides a numerical summary of the data. Scatterplot graphically displays the data. Click the "Show least-squares line" checkbox to display the least-squares regression line and equation. To help assess the fit of the regression line select the Residuals plot tab.
Note: Some calculated values are reported using scientific notation. In such cases "e" stands for a power-of-ten exponent. For example, 1.0e3 = 1.0 x 103, 1e-3 = 1.0 x 10-3.