68 % of kids watch tv daily. out of 12 kids what is the probability that:

a. Exactly six kids watch tv daily
b. Six or less kids watch tv daily
c. Seven or more kids watch tv daily
d. Find the mean for the distribution

2 answers

This is a case of binomial distribution

Prob(watching) = .68/100 = 17/25
prob(not watching) = 8/25

a) Prob(exactly 6 out of 12 watching)
=C(12,6)(17/25)^6(8/25)^6 = ....

b) prob(6 or less)
= Prob(exactly 1) + Prob(exacly 2) + prob(exactly 3) + .. prob(exactly 6)
= C(12,1)(17/25)(8/25)^11 + C(12,2)(17/25)^2(8/25)^10 + .. + C(12,6)(17/25)^6(8/25)^6

do the others the same way
hope you have a good calculator.
We can use excel for this. do you know how I would set it up in excel?