I got these searching "Linear Regression Online Calculators." There are probably many more, if you find one you like, email me the link, please!
1) Alcula - Pros: Easy to read, provides graph, sample size (n), x-bar, y-bar, a, b and regression equation in proper y = a + bx form, provides list of data entered, can calculate predicted values (y-hat) for a given x, 14 non-zero digits of accuracy. Cons: Does calculate Correlation coefficient (r) but have to go to 2nd page, doesn't provide r-squared (can get from r), seems kinda slow to process.
2) MathPortal.Org - Pros: Easy to read, provides graph, lists data input, proper y = a + bx format, provides explanation of work. Cons: Have to use 2nd page for Correlation coefficient (r), doesn't provide r-squared (can get from r), doesn't list a and b separately, only gives values to 1000ths (won't work well with real small numbers), no predicted values.
3) GraphPad - Pros: Easy to use, enter data in lists like calculator, , provides Coefficient of Determination (r-squared), provides info for later sections (95% C.I. for slope, x and y intercepts, P-values) Cons: Uses y = bx + a format (a and b not given, just in equation), doesn't provide data list (useful to check accuracy of data input), worked great once, can get to work again.
4) Correlation and Regression applet - Pros: from publisher of book, quick visual exploration of regression - does not use numbers, can easily explore data such as outliers, changing one observation or adjusting clustering. Good for testing conjectures about data. Cons: No input of numbers, not for use in getting a regression equation for specific data.
