SOLUTION: Assume that when adults with smartphones are randomly selected, 55% use them in meetings or classes. If 7 adult smartphone users are randomly selected, find the probabili
Algebra ->
Probability-and-statistics
-> SOLUTION: Assume that when adults with smartphones are randomly selected, 55% use them in meetings or classes. If 7 adult smartphone users are randomly selected, find the probabili
Log On
Question 1167372: Assume that when adults with smartphones are randomly selected, 55% use them in meetings or classes. If 7 adult smartphone users are randomly selected, find the probability that at least 4 of them use their smartphones in meetings or classes. Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! This is a binomial with n=7 p=0.55
a least 4 of them use their smartphones
that is 1-prob(3) of them use them.
=0.6083 is answer.
probability 4 use them is 7C4*0.55^4*0.45^3=0.2918
for 5 it is 0.2140
for 6 it is 0.0872
for 7 it is 0.55^7 or 0.0152
add them to get 0.6082 (rounding error)
