42​% use them in meetings or classes. If 8 adult smartphone users are randomly​ selected, find the probability that at least 4 of them use their smartphones in meetings or classes.

Answer 1

Presumably this is a question using the binomial distribution.

The answer is the sum of terms ₈C_k * (.42)^k * (.58)^8-k from k = 4 to 8 where ₈C_k is the binomial coefficient.