I'm looking for a relatively inexpensive and easy to use calculator
that would be effective for determining the following information:

-Standard Deviation
-Variance
-Probabilities
-Confidence intervals for population mean and variance from sample
statistics
-p-values for hypotheses about population mean from sample data
-Simple Regression
etc.

It should be easy to use (for instance, include a clear instruction
manual) and relatively inexpensive (I don't really have an idea of the
price range but hope to spend less than $100).

Please let me know if you require any further clarification on what I
am looking for.

Hi jpbischke,

When I was taking a statistic course, the TI-83+ calculator was best
suited for statistics calculation.  It is a general-purpose graphing
calculator, but the features you desire are included, plus more.  Note
that only the TI-83 has the statistics capability, the TI-85 does not,
and the TI-86 needs a program downloaded from the Internet.
The calculator costs around $100.  Since it's from Texas Instrument,
you should expect a comprehensive manual.  You can shop around for it
here: http://froogle.google.com/froogle?q=TI-83+Plus

Hope that it's helpful,
secret901-ga

I agree with secret901 - the TI-83+ is probably the cheapest
calculator for what you want, and the TI series calculators have great
manuals. Since it's back to school time, look for special sales - my
local Circuit City is selling em for $70 right now. If you want a
better general purpose calculator, the TI-86 and TI-89 are both quite
nice (though a little more expensive) and will also do the same
statistics.