### Two-variable Statistical Calculator

(Correlation and Regression)

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 10^{3}, 1e-3 = 1.0 x 10^{-3}.

**TITLE:** Two-variable Statistical Calculator

**FORMAT:** Java applet

**SOURCE:** Moore, et al., *Introduction to the Practice of Statistics,* Fifth Edition, W. H. Freeman & Co.

© 2006 W. H. Freeman & Co. and Sumanas, Inc.