At an airport, 78% of recent flights have arrived on time. A sample of 11 flights is studied. Find the probability that exactly 7 of them were on time.
A) 0.1358
B) 0.0014
C) 0.8642
D) 0.0030

Question

Quizplus · Accepted Answer

This is a binomial probability problem, where n = 11 (number of trials), k = 7 (number of successes), p = 0.78 (probability of success on a single trial), and q = 1 - p = 0.22 (probability of failure). The binomial probability formula is P(X = k) = (nCk) * p^k * q^(n-k). Plugging in the values, we get P(X = 7) ≈ 0.1358.

At an Airport, 78% of Recent Flights Have Arrived on Time