Find the probability that more than 2 students will attend. (Round your answer to four decimal places.)

Question

A school newspaper reporter decides to randomly survey 12 students to see if they will attend Tet (Vietnamese New Year) festivities this year. Based on past years, she knows that 20% of students attend Tet festivities. We are interested in the number of students who will attend the festivities.

Answer 1

x the number of students that will attend is a binomial variable. the probability that x = k students will attend is

n! p^k (1-p)^(n-k)

----

k! (n-k)!

where n is the number of students surveyed (12), p is the probability that a student will attend (= 0.20).

The probability that more than 2 will attend is equal to 1 - the probability that 0, 1 or 2 will attend.

Compute the probabilities using the above formula for k = 0, 1 and 2, sum the probabilities then subtract from 1.