A poll is given, showing 60% are in favor of a new building project. If 9 people are chosen at random, what is the probability that exactly 4 of them favor the new building project?

Respuesta :

Answer:

The probability that exactly 4 are in favor the new building project is 0.1672.

Step-by-step explanation:

Let X denote the number of people who are in favor of a new building project.

The proportion of people who are in favor of a new building project is, p = 0.60.

A random sample of n = 9 people are chosen.

Every person has independent opinion about the new building project.

Thus, the random variable X follows a binomial distribution with parameters n = 9 and p = 0.60.

Compute the probability that exactly 4 are in favor the new building project as follows:

[tex]P(X=4)={9\choose 4}(0.60)^{4}(1-0.60)^{9-4}\\\\=126\times 0.1296\times 0.01024\\\\=0.167215104\\\\\approx 0.1672[/tex]

Thus, the probability that exactly 4 are in favor the new building project is 0.1672.