Question

Assume that when adults with smartphones are randomly​ selected, 35​% use them in meetings or classes. If 7 adult smartphone users are randomly​ selected, find the probability that exactly 4 of them use their smartphones in meetings or classes.

Answer 1

This can be solved by using the binomial distribution, as follows:
$P(4\ users)=7C4\times0.35^{4}\times0.65^{3}=0.144$
The answer is: 0.144 to 3 dp.