Say, I was rolling a dice and need to get a 6. I know that my probability of rolling a 6 on any single throw will be 1/6. Now, let's say I'm rolling the dice every 2 seconds for 1 minute, therefore getting 30 rolls.

 

What would be the correct way to calculate expected number of sixes I will roll? Part of me wants to simply say, that it's 5, but something tells me it might not be that simple.

Good intuition. Check out the binomial distribution to see why you're right.

Thanks! I'll check it out!

Just in case you have not figured the answer out yet, let me give you some hints. No matter how many times you roll the dice, the probability of you getting a 6 each time will still be 1/6. Now the chance is 1/6 and the number of trials is 30, what would the number of 6s you get?

 

I have a young cousin who had no idea about probability and I tried my very best to help him. If you still find it hard to understand, try using the link that Mr. Prometheus provided. Or you might want to look at some other sites about Binomial Distribution.