T-Test and Regression Analysis
 

Where can I find some free software?

If you already have excel, it will do that for you.

Otherwise OpenOffice will work for you.

You could also get a free 30 day trial of Minitab, which i've been using for a few things :D
Minitab has much better regression analysis than excel (cause it's a statistics package). So if you're doing other multivariate regression or non-parametric regression, with non -parametric tests, minitab trial would be good.

Otherwise, if it's just ordinary least sqaures, then excel/openoffice/gnumeric would be ok.
On excel you'll probably have to install the data analysis tool, but it's easy to do, as long as you have the office cd!

Thanks folks ;-) !

For my stats class we had to use R.

http://www.r-project.org/

SPSS is the best stats program I have found. I dont know if you can get it somewhere free unless you know someone who will burn it for you like I did.

SAS is my favorite, I'm fairly certain it's not free. It involves writing your own code, but once it's understood, it's far more efficient and easy to use than SPSS. Check it out sometime if you're interested in investing some cash in a great package.

http://faculty.vassar.edu/lowry/VassarStats.html

Is a wonderful web-based set of statistical tools. Unfortuanatly it con't do terribly complex computations, but on the plus side it has a sort of online textbook that will explain the concepts (great for my stats class last semester).

i'd recommend the free 30 day trial version of Spss and find yourself a crack.