A comedy club hosts an amateur comedy night, a good opportunity for aspiring comedians to

perform. Of the 8 amateur comedians who signed up for tonight's show, 6 perform satirical

comedy,

If the host randomly selects 4 comedians from the sign-up list, what is the probability that all

of them practice satirical?

Write your answer as a decimal rounded to four decimal places.

Respuesta :

Answer:

0.2143 probability that all of them practice satirical.

Step-by-step explanation:

The comedians are chosen without replacement, which means that the hypergeometric distribution is used to solve this question.

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

In this question:

8 comedians means that [tex]N = 8[/tex]

6 practice satirical means that [tex]k = 6[/tex]

Sample of 4 means that [tex]n = 4[/tex]

What is the probability that all of them practice satirical?

This is P(X = 4). So

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]

[tex]P(X = 4) = h(4,8,4,6) = \frac{C_{6,4}*C_{2,0}}{C_{8,4}} = 0.2143[/tex]

0.2143 probability that all of them practice satirical.