Question

Suppose you have six people participating in a completely randomized comparative experiment. Three people will receive the treatment and three the placebo. Give the number of possible ways to choose the three subjects who will receive the treatment.

Answer 1

20.

Explanation:

This can be solved using combination technique. Since we have to choose 3 out of 6 and their order is not considered. Thus,

6 combination 3

= 6C3

=
`(6!)/(3!*(6-3)!)`

=
`(6*5*4*3!)/(3!*3!)`

=
`(6*5*4)/(3*2*1)`

=
`(6*5*4)/(6)`

= 5*4

= 20 ANSWER