Amit is going to guess on all

2

0

2020 questions of his multiple-choice test. Each question on the test has

4

44 answer options, and only one is correct.

What is the best prediction for the number of questions that Amit will answer correctly?

Choose 1 answer:

Close to five but not exactly 5

Step-by-step explanation:

Khan Academy

The best prediction for the number of questions that Amit will answer correctly is 5.

Step-by-step explanation:

Each question can be considered as an independent Bernoulli trial. This implies that we have 20 independent trials.

Now, the probability of making a correct guess on each question is;

1/4. This is because we have 4 choices per question and only 1 is correct.

If we now let the random variable X denote the number of questions that Amit will answer correctly, then X is a Binomial random variable with parameters;

20 and 1/4.

The expected number of correct answers is simply the product of these two values;

20 * (1/4) = 5

Therefore, the best prediction for the number of questions that Amit will answer correctly is 5