Question

Assume that when adults with smartphones are randomly​ selected, 52​% use them in meetings or classes. If 15 adult smartphone users are randomly​ selected, find the probability that fewer than 3 of them use their smartphones in meetings or classes.

The probability is . ​(Type an integer or decimal rounded to four decimal places as​ needed.)

Answer 1

Let , X be the number of adults who  use their smartphones in meetings or classes.

Here , X has binomial distribution with parameter n=15 and p=52%=0.52

The probability mass function of X is ,

; x=0,1,2,.........,n and q=1-p

= 0 ; otherwise

Now ,

Therefore , the probability that fewer than 3 of them use their smartphones in meetings or classes is 0.0023