This is the problem that I am stuck on.There are 8 black, 4 red, 2 green, and 1 gold stars in a bag; the probability of randomly selecting a gold star, replace it, then a gold star is _____. Make sure you show your calculations and explain your solution in detail. Thank you!
Tutor.com

In this video, Salman Khan of Khan Academy explains probability. Part 8 of 8.
Khan Academy


A helpful scientific calculator that runs in your web browser window.
Holt Online Learning

This site will help you convert from one measurement to another one. Lots of conversion to look at.
Tank Depot

Gives some basic rules for probabilty such as mutually exclusive or disjoint
Richland

In this video, Salman Khan of Khan Academy explains probability density functions.
Khan Academy

In this video, Salman Khan of Khan Academy explains probability. Part 3 of 8.
Khan Academy

If you need to check your conversion, you can use this site. You enter your conversion and it will do it for you. Great way to check your answers.
General Units

Very detailed explanation of permuataions and combinations
Ask Dr. Math
