You can search this electronic textbook for statistics topics including ANOVA, linear regression models, the effects of outliers, confidence intervals, etc. Gives explanations and discusses the topics.
StatSoft

Site gives detailed information for constructing a least squares regression line.
Stat Trek.com

This website provides graphical displays, an index of online calculators and summaries of main topis in statistics.
Statistics to Use

This site is designed to provide information, demonstrations, links and quizzes associated with the statistics and statistical methods for research design and analysis. It includes tuorials and applets
WebStat

Online Textbook for a variety of statistical tests
Statistica Website

The website indexes lectures in Introduction to Statistical Methods course.
Lecture Summaries: Introduction to Statistical Methods

Very comprehensive list of statistics formulas.
Stat Trek

It also gives formulas, description, etc for statistics.
Wolfram Mathworld

Interactive applet that allows a student to plot points on a graph and see how an outlier affects the regression line of the data points.
Illuminations NCTM

Site has defintion and explanation of the least squares regression line as well as links to additional resources.
Carlton College Statistics
