Statistics Question

Question

 How many ways are there to select 4 candidates from 9 equally qualified recent graduates for openings in an accounting firm?

Answer 1

This is a math problem in combination. The question is like to ask how many combinations we have if we want to choose 4 people out of 9 people.

Let’s do a similar problem. There are 7 ice creams at the store, if you want to choose 3 ice creams out of these 7 ice creams, how many ways can you have your 3 ice creams?

In math, we solve it by a combination formula C(7, 3) = 35.

Specifically, to calculate C(7, 3), we have C(7, 3) = 7! / (3! 4!) = 35.

The sign “!” is an operator called factorial. Just like +, -, this ! is an operator, a way to do some kind of calculation. Specially, 7! = 7*6*5*4*3*2*1, and similarly 3! = 3*2*1. You can try 4! now on your own.

Similarly, you can try the original problem.

In general, there are C(n, m) ways to select m items out of n items.