Question

A dice is rolled 20 times and the number of twos that come up is tallied. Find the probability of getting exactly four twos.
A. 0.202
B. 0.075
C. 0.101
D. 0.083

Answer 1

This is a binomial probability distribution problem

so you'll use the formula

P(X = k) = (n C k)*(p)^k*(1-p)^(1-k)

Answer 2

in this case,

n = 20
p = 1/6 = 0.16667
k = 4

Answer 3

hmmm. ok