Answer:
a) 0.2725
b) 0.7275
c) 0.8948
Step-by-step explanation:
This is a binomial distribution probability problem. The formula is:
[tex]P(x)=\frac{n!}{(n-x)!x!}p^{x}q^{n-x}[/tex]
Where
n is the number of trials [here we are taking 8 person, so n = 8]
x is what we are looking for [in the problem]
p is the probability of success [ 15%, so p = 0.15
q is the probability of failure [q = 1-p = 0.85]
Now,
a)
We are looking for "no one" did fling, so x = 0
Let's put into formula and find out the probability:
[tex]P(x=0)=\frac{8!}{(8-0)!0!}(0.15)^{0}(0.85)^{8}\\P(x=0)=0.2725[/tex]
So, the probability that no one has done a one-time fling is 0.2725
b)
Atleast 1 person means P(x ≥ 1).
This can be found by:
P(x ≥ 1) = 1 - P(x=0) = 1 - 0.2725 = 0.7275
THus, Probability that at least one person has done a one-time fling is 0.7275
c)
No more than 2 people means P (x≤2).
This is essentially
P ( x ≤ 2 ) = P(x=0) + P(x=1) + P(x=2)
P ( x = 0 ) is found in part (a), which is 0.2725
P (x = 1 ) and P(x=2) can be found using formula:
[tex]P(x=1)=\frac{8!}{(8-1)!1!}(0.15)^{1}(0.85)^{7}\\P(x=1)=0.3847[/tex]
and
[tex]P(x=2)=\frac{8!}{(8-2)!2!}(0.15)^{2}(0.85)^{6}\\P(x=2)=0.2376[/tex]
Thus,
P ( x ≤ 2 ) = P(x=0) + P(x=1) + P(x=2) = 0.2725 + 0.3847 + 0.2376 = 0.8948
