Probability calculation

My math skills have declined rather rapidly. My question should be fairly simple. How do I calculate the chance of an occurance within probabilty. That probably didn't make any sense.

Let's say I create a random number between one and four and make a guess and count how many times I guess correctly. Probability is I guess correct 25% of the time. Let's say I guess ten million times. If my result is that I guessed right 30% of the time, how do I calculate the chance that that could occur? How do I calculate the standard deviation for such a case and how many deviations my result was?

Formulas would be great. Websites explaining this basic stuff would be great too (maybe help nudge my noggin back in place). Thanks.

I took stat last year but my teacher blew nuts....so I can't really help you with formulas. If you check the wolfram web site they have almost everything math....i think its wolfram...try googling it.

really wish I had a better teacher

i just know standard deviation is something like sqrt(xmean - x / xmean)

or something that looks like that. finding probabilities of certain events like that may get a little tougher, because then you start getting into your probability curves, and knowing the area underneath usually requires looking in a table. Try looking up Z Scores...thats the curve you want.

sorry this is so much rambling...trying to pull together the little I learned in stat for you :wave: good luck!

http://math.sierra.cc.ca.us/Statisti...csformulas.asp

Some formulas there for you... all I did was search google for statistics formulas then hit I'm feeling lucky ;) Google rocks.