[phantomworker]

This is very elementary statistics. Stat 101. Or even Psych 101 teaches statistical hypothesis testing. It has nothing to do with odds. ;) You might find a more layman's explanation on google or yahoo.com If you'd like, I can explain it a little more. Just let me know. I also taught statisics as a grad student.

http://www.physics.csbsju.edu/stats/t-test.html

http://www.texasoft.com/winkpair.html

[Emmalein]

I also taught statisics as a grad student.

I could have used your help the 1st time I took stats. lol

[neverdem]

Thanks for the links. "Assumptions: The observed data are from the same subject or from a matched subject and are drawn from a population with a normal distribution."

Let me go out on a limb and say that since all the females apparently had no observable change in deoxyhemoglobin at the nucleus accumbens, and all the males did, I don't believe there's a normal distribution here. The dimorphism coincides with a biphasic distribution.