Problema Solution

In your town, the number of individuals voting in the next election is 800. Of those voting, 600 are Republicans. If you randomly sample 60 individuals, one at a time, from voting population, what is the probability there will be 42 or more Republicans in the sample? Assume the probability of getting a Republican on each sampling stays the same.

Answer provided by our tutors

probability of getting a Republican on each sampling = 600 / 800 = 3 / 4

so ,   the probability there will be r no of Republicans in the sample is = 

60Cr (3/4)^r (1-3/4)^60-r

now,   the probability there will be 42 or more Republicans in the sample is

Σ 60Cr (3/4)^r (1-3/4)^60-r   where r ranges from 42 to 60..

find the summation .it is our required answer