Assume that when adults with smartphones are randomly selected, 49% use them in meetings or classes. If 14 adult smartphone users are randomly selected, find the probability that fewer than 4 of them use their smartphones in meetings or classes.

Probability of fewer than 4 = 0.0339

Explanation:

This is a question on binomial distribution. It is a distribution which has two possible outcome; a success or a failure

Probability of success (p) = 49%

Probability of failure (q) = 1 - 49% = 1-0.49

Probability of failure (q) = 0.51 = 51%

n = 14

P(X = x) = (n!)/[(n-x)!x!] × p^x × q^(n-x)

Probability of fewer than 4 = Pr(X <4)

Pr(X <4) = Pr(X = 0) + Pr(X = 1) +Pr(X = 2) +Pr(X = 3)

Find attached the workings

From the workings, Pr(X <4) = 0.0339295

Probability of fewer than 4 = 0.0339 (approximately)

the answer would be c