Question

Assume that when adults with smartphones are randomly​ selected, 55​% use them in meetings or classes. If 6 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

it is a binomial probability distribution, because there is fixed number of trials,  
only two outcomes are there, success and failure  
trails are independent of each other  
and probability is given by  

P(X=x) = C(n,x)*px*(1-p)(n-x)

where  
Sample size , n =    6
Probability of an event of interest, p =   0.55

Required probability = P ( X =    2   ) = C(6,2) * 0.55^2 * (1-0.55)^4 =            0.1861(answer)