In: Statistics and Probability
A group consists of 6 men and 5 women. Four people are selected to attend a conference.
a. In how many ways can 4 men be selected from this group of 11?
b. In how many ways can 4 men be selected from the 6 men?
c. Find the probability that the selected group will consist of all men. Would this be unusual?
SOLUTION:
A group consists of 6 men and 5 women. Four people are selected to attend a conference.
Please note nCx = n! / [(n-x)!*x!]
a. In how many ways can 4 men be selected from this group of 11
The number of ways of selecting 4 men out of 11 = 11C4 = 11! / [(11-4)!*4!]
= 11!/(7!*4!)
= 330 ways
b. In how many ways can 4 men be selected from the 6 men?
4 mean cab be selected from the 6 men in 6C4 ways = 6!/[(6-4)!*4!]
= 6!/(2!*4!)
= 15 ways
c. Find the probability that the selected group will consist of all men. Would this be unusual
Probability = Favourable outcomes/Total Outcomes
Favourable outcomes all 5 are men = 6C5 = 6
Total Outcomes = 5 people out of 11 = 11C6 = 462
Therefore the required probability = 6/462 = 1 / 77 = 0.013