Question

Assume that when adults with smartphones are randomly​ selected, 38​% use them in meetings or classes. If 30 adult smartphone users are randomly​ selected, find the probability that exactly 19 of them use their smartphones in meetings or classes.

Answer 1

Percentage of randomly selected adults with smartphones using them is meetings or classes = 38%

Probability of a randomly selected adult with smartphones using them is meetings or classes :p = 38/100 = 0.38

Binomial distribution will used to find the Probability that exactly 19 of them use their smartphones in meetings or classes

Binomial Distribution:

If 'X' is the random variable representing the number of successes, the probability of getting ‘r’ successes and ‘n-r’ failures, in 'n' trails, ‘p’ probability of success ‘q’=(1-p) is given by the probability function

For the given problem,

X : Number of randomly​ selected adults with smartphone users use them in meetings or classes.

n : Number of randomly​ selected adult smartphone users = 30

p: Probability of a randomly selected adult with smartphones using them is meetings or classes = 0.38

q = 1-p = 1-0.38 = 0.62

Probability of 'r' adults using smart phone in a meetings or classes from 'n' adults with sart phones =

Probability that exactly 19 of them use their smartphones in meetings or classes = P(X=19)

Probability that exactly 19 of them use their smartphones in meetings or classes = 0.00295