If you read this problem:
"An urn contains n balls, one of which is special. If k of these balls are withdrawn one at a time, with selection being equally likely; what is the probability that the special ball is chosen?"
And have no idea of what it means but would like to know. Then this course is for you.
It will cover in a very friendly way: Counting, Permutations, Discrete Probabilities, Poisson, Binomial and Normal Distributions