Westonci.ca is the premier destination for reliable answers to your questions, provided by a community of experts. Discover precise answers to your questions from a wide range of experts on our user-friendly Q&A platform. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

Select the correct answer.
The chaperones for a field trip to the museum will be 7 history teachers and 13 science teachers. Each student on the trip will be assigned to a
group led by two chaperones.
What is the approximate probability that a random student on the trip will be assigned to a group led by two history teachers?
O A
11.1%
ОВ.
2.3%
Ос.
28.6
OD. 12.3

Sagot :

Answer:

A 11.1%

Step-by-step explanation:

The students are chosen from a sample 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, we have that:

13 + 7 = 20 teachers, which means that N = 20.

7 history teachers means that k = 7.

Two teachers for each student, which means that n = 2.

What is the approximate probability that a random student on the trip will be assigned to a group led by two history teachers?

This is P(X = 2). 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 = 2) = h(2,20,2,7) = \frac{C_{7,2}*C_{13,0}}{C_{20,0}} = 0.1105[/tex]

So close to 11.1%, and the correct answer is given by option A.

Answer:

A

Step-by-step explanation: