Question

Assume that when adults with smartphones are randomly selected, 37% use them in meetings or classes. If 5 adult smartphone users are randomly selected, find the probability that exactly 3 of them use their smartphones in meetings or classes. 

The probability is _______ (Round to four decimal places as needed.)

Answer 1

Solution

Given that ,

p = 0.37

1 - p = 0.63

n = 5

x = 3

Using binomial probability formula ,

P(X = x) = ((n! / x! (n - x)!) * p^x * (1 - p)^{n - x}

P(X = 3) = ((5! / 3! (5 - 3)!) * 0.37³ * (0.63)^{5 - 3}

= 0.2010

Probability = 0.2010

Answer 2

SOLUTION :

p = adults with smartphones = 37% = 0.37

q = adults without smartphones = 1 -  0.37 = 0.63

As per binomial distribution : For n = 5 :

P(x = 3) 

= ncr(5, 3)*(0.37)^3 * (0.63)^2

= 0.2010 (ANSWER).