Question

A student is about to take a true-false, 5-question quiz, with absolutely no knowledge of the subject. So, the student flips a coin to determine their response to each question. If you let the random variable X = "a number of correct answers on the quiz," what is the correct histogram?

Answers are from 1-4, and they are all in order.

Answer 1

Using the binomial distribution, considering the probability of each event, the correct histogram is the fourth one.

For each question, there are only two possible outcomes, either the student guesses the correct answer, or not. The probability of guessing the correct answer on a question is independent of any other question, hence the binomial distribution is used to solve this question.

What is the binomial distribution formula?

The formula is:

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$C_{n,x} = \frac{n!}{x!(n-x)!}$

The parameters are:

• x is the number of successes.

• n is the number of trials.

• p is the probability of a success on a single trial.

In this problem:

• There are questions, hence n = 5.

• They are true-false questions, that is, they have one correct option out of 2, hence p = 0.5.

Then, the probabilities are as follows:

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{5,0}.(0.5)^{0}.(0.5)^{5} = 0.03125$

$P(X = 1) = C_{5,1}.(0.5)^{1}.(0.5)^{4} = 0.15625$

$P(X = 2) = C_{5,2}.(0.5)^{2}.(0.5)^{3} = 0.3125$

$P(X = 3) = C_{5,3}.(0.5)^{3}.(0.5)^{2} = 0.3125$

$P(X = 4) = C_{5,4}.(0.5)^{4}.(0.5)^{1} = 0.15625$

$P(X = 5) = C_{5,5}.(0.5)^{5}.(0.5)^{0} = 0.03125$

Hence the fourth histogram is correct.

More can be learned about the binomial distribution at https://brainly.com/question/14424710