Given:
There are number of trials and possibility of success
Required:
We need to find the probability by binomial distribution formula
Explanation:
A)
n=15
p=0.4
q=0.6
x=4
Substitute the values in the formula
[tex]P(4)=\frac{15!}{11!4!}(0.4)^4(0.6)^{11}=0.12[/tex]
B)
n=12
p=0.2
q=0.8
x=2
Substitute the values in the formula
[tex]P(2)=\frac{12!}{10!2!}(0.2)^2(0.8)^{10}=0.28[/tex]
C)
n=20
p=0.05
q=0.95
x=0,1,2,3
Substitute the values in the formula
[tex]\begin{gathered} P(0)=\frac{20!}{20!0!}(0.05)^0(0.95)^{20}=0.35848 \\ \\ P(1)=\frac{20!}{19!1!}(0.05)^1(0.95)^{19}=0.37735 \\ \\ P(2)=\frac{20!}{18!2!}(0.05)^2(0.95)^{18}=0.18867 \\ \\ P(3)=\frac{20!}{17!3!}(0.05)^3(0.95)^{17}=0.0.05958 \end{gathered}[/tex]
Now add all
[tex]P(atmost\text{ 3\rparen}=0.98408[/tex]
Final answer:
A) 0.12
B) 0.28
C) 0.98408