Question

What is ${}^{n}C_r$ in probability?

Answer 1

Interpretation of ${}^{n}C_r$.

In probability, ${}^{n}C_r$ is the number of ways of selection of $r$ elements from a set of $n$ elements, such that the order of elements does not matter.

Formula: ${}^{n}C_r=\frac{n!}{r!\left(n-r\right)!}$