What’s the probability

Question

Assume that when adults with smartphones are randomly selected, 53% use them in meetings or classes. If 10 adult smartphone users are randomly selected, find the probability that at least 3 of them use their smartphones in meetings or classes

Answer 1

This is a binomial distribution with the parameters n and p.

n = 10 adults use their smartphones

p = 0.53 (success probability of adults using smartphones in meetings or classes)

x = 3 adults selected use their smartphones

We want to set up the binomial distribution probability formula.

P(X = x) = C(n, x)*p^x*(1 - p)^{n - x} = [n! / [x!*(n - x)!]] *p^x*(1 - p)^{n - x}

P(X ≥ 3) = 1 - P(X < 3) = 1 - [P(X = 0) + P(X = 1) + P(X = 2)] = 1 - 0.0366 = 0.9634

The probability that at least 3 adults use their smartphones in meetings or classes is 0.9634.