Question

Assume that when adults with smartphones are randomly​ selected, 51​% use them in meetings or classes. If 8 adult smartphone users are randomly​ selected, find the probability that at least 2 of them use their smartphones in meetings or classes.

Answer 1

Solution:

Given: Adults with smartphones are randomly​ selected.

p = probability that adults with smartphones use them in meetings or classes = 51% = 0.51

n = Number of  adult smartphone users are randomly​ selected = 8

X = Number of adult smartphone users uses smartphones in meetings or classes follows a Binomial distribution with n =8 and p=0.51.

We have to find: the probability that at least 2 of them use their smartphones in meetings or classes.

That is:

Thus using Binomial probability formula:

where

q =1 - p = 1 - 0.51 = 0.49

and

thus

and

thus

(Round final answer to specified number of decimal places)

Thus the probability that at least 2 of them use their smartphones in meetings or classes is 0.9690.