Question

Cell phones and surveys ii the survey by the national center for health statistics further found that 49% of adults ages 25–29 had only a cell phone and no landline. we randomly select four 25–29-year-olds:
a.what is the probability that all of these adults have a only a cell phone and no landline?
b.what is the probability that none of these adults have only a cell phone and no landline?
c.what is the probability that at least one of these adults has only a cell phone and no landline?

Answer 1

The following is the solution for the problems given above:

A. The probability that all adults have only a cellphone is P(only cellphone) = 0.49 ^ 4 = 0.0576
B. If 49% only have a cellphone and no landline, then only 51% don’t have this combination of phones, so therefore: P (no one with only a cellphone) = 0.51^4 = 0.0677
C. If at least one of them has a cellphone: P (at least one with cell phone) = 1 – P(cellphone and/or landline) = 1 – (0.51)^4 = 0.9323