Question

# Assume that when adults with smartphones are randomlyselected, 57...

Assume that when adults with smartphones are randomly selected, 57

57% use them in meetings or classes. If 15

15 adult smartphone users are randomly selected, find the probability that fewer than 4

4 of them use their smartphones iThe probability is

nothing

.

(Type an integer or decimal rounded to four decimal places as needed.)n meetings or classes.

Answer & Explanation

Solved by verified expert

answer = 0.0040

Step-by-step explanation

here we use binomial probability distribution

P(x) = ^{n}C_{x} *p^{x}*(1-p) ^{n-x}

we are given that p=0.57, n=15

hence

P(x < 4) =P(x=0) + P(x =1) + P(x=2) + P(x=3)

P(x=0) =^{15}C_{0}*0.57^{0} (1-0.57)^{15-0 }+^{15}C_{1}*0.57^{1} (1-0.57)^{15-1 }+^{15}C_{2}*0.57^{2} (1-0.57)^{15-2} +^{15}C_{3}*0.57^{3} (1-0.57)^{15-3}

= 0.00000 + 0.00006 + 0.00059 + 0.00337 ^{}

^{ =} 0.0040