Standard Deviation List question

Hi,

Can you tell me how I would solve a question similar to the following?

Let's say I have the following list representing scores on an exam for 3 students

student: a b c
test 1: 4 5 6
test 2: 7 5 9
test 3: 4 2 1

how can I find which student had the biggest standard dev and the smallest?

I know this is very simple but I'm just confused when the list is a lot bigger what the quickest way would be.

Thanks!