105 of the population is 65 or older Find the probability th

10.5% of the population is 65 or older. Find the probability that the following number of persons selected at random from 25 people are 65 or older. The probability that all are 65 or older is

Solution

p = 10.5% = 0.105

q = 1- 0.105 = 0.895

Binomial probability distribution: nCr(p)^r(q^(n-r) )

n = 25 ; r = 25

Probability of all people older than 65 or older = 25C25(0.105)^25

= 0.000