How do you fine the P-value?

Here are a few articles that explain what a p-value is, with examples. One of them is a youtube link, if you so prefer.

http://www.stat.ualberta.ca/~hooper/teaching/misc/Pvalue.pdf
http://www.youtube.com/channel/HCM26EC2x5oEU
http://en.wikipedia.org/wiki/P-value