# Multivariate Quantitative Relationships

• ### Understanding the Least-Squares Regression Line

This applet allows students to explore three methods for measuring "goodness of fit" of a linear model. Users can manipulate both the data and the regression line to see changes in the square error, the absolute error, and the shortest distance from the data point to the regression line.
• ### Intuitive Biostatistics: Choosing a Statistical Test

This page provides a table for selecting an appropriate statistical method based on type of data and what information is desired from the data. It also compares parametric and nonparametric tests, one-sided and two-sided p-values, paired and unpaired tests, Fisher's test and the Chi-square test, and regression and correlation. It comes from Chapter 37 of the textbook, "Intuitive Biostatistics".
• ### Quote: Fiedler on Forecasting

Forecasting is very difficult, especially about the future. A quote of business economist Edgar R. Fiedler (1929 - 2003) found in "Across the Board", the magazine of The Conference Board, Inc. (June, 1977). The quote also appears in "Statistically Speaking: A dictionary of quotations" compiled by Carl Gaither and Alma Cavazos-Gaither.
• ### Quote: Wells/Wilks on Statistical Thinking

Statistical thinking will one day be as necessary for efficient citizenship as the ability to read and write! Quote from the presidential address in 1951 of mathematical statistician Samuel S. Wilks (1906 - 1964) to the American Statistical Association found in "JASA",Vol. 46, No. 253., pp. 1-18. Wilks was paraphrasing Herbert G. Wells (1866 - 1946) from his book "Mankind in the Making". The full H.G. Wells quote reads: "The great body of physical science, a great deal of the essential fact of financial science, and endless social and political problems are only accessible and only thinkable to those who have had a sound training in mathematical analysis, and the time may not be very remote when it will be understood that for complete initiation as an efficient citizen of one of the new great complex worldwide States that are now developing, it is as necessary to be able to compute, to think in averages and maxima and minima, as it is now to be able to read and write."
• ### Joke: Weighing Trees

A quick pun about the "log scale" by Bruce White
• ### Joke:car sales trends

A quick pun about "autocorrelation" by Bruce White.
• ### Calculator Instructions for Elementary Statistics

This website provides links to instructions for performing basic statistics such as confidence intervals, hypothesis tests, discrete distributions, linear regression, etc. for TI 83, TI 84, and TI 86 calculators.
• ### Correlation, Determination, and Causality In Introductory Statistics

This article discusses teaching causality without being discipline specific. It explains the causal differences between description, prediction and explanation.
• ### **National Library of Virtual Manipulatives: Scatterplot

This Java Applet of a scatterplot allows you to enter data, move data points, define the range of values, and view graph value information.
• ### Spinning Wheel

This activity uses a computer program to explore probability concepts such as sample space, independent events, law of large numbers, and reliability. An outline of the activity and the computer program are provided.