Suppose that there is a 085 probability that a randomly sele

Suppose that there is a 0.85 probability that a randomly selected adult knows what twitter is.

Use the binomial probability formula and the addition rule to find the probability of getting 0 or 1 adults who know what twitter is when 4 adults are randomly selected?

Solution

4 ARE SELECTED

BINOMIAL

TO CHECK EITHER 0 OR 1 KNOW

1) FOR 0

4C0(0.85)^0*(0.15)^4 = 0.005

FOR 1

4C1*(0.85)^1*(0.15)^3 = 0.11

ADDNING BOTH WE WILL GET 0.115