Question

(5.2.17) Assume that when adults with smartphones are randomly​ selected, 45​% use them in meetings or classes. If 5 adult smartphone users are randomly​ selected, find the probability that exactly 2 of them use their smartphones in meetings or classes
The probability is?

Answer 1

variations to choose 2 users from 5 is ${5 \choose 2}$ . chance that 2 users from 5 use their smartphones in meetings or classes is $0.45^2*0.55^3$ . Means probability is

${5 \choose 2}*0.45^2*0.55^3=\frac {5!} {2!3!}*0.45^2*0.55^3=0.3369$ or 33.69%