Question

In a binomial probability scenario with 30 questions on a test, find the probability of getting exactly 18 correct.

A) 0.117
B) 0.285
C) 0.182
D) 0.224

Answer 1

To find the probability of getting exactly 18 correct out of 30 questions on a test, we can use the binomial probability formula. Plugging in the values into the formula, we get approximately 0.285. Therefore, the correct answer is B) 0.285.

Step-by-step explanation:

To find the probability of getting exactly 18 correct out of 30 questions on a test, we can use the binomial probability formula:

P(X = k) = C(n,k) * p^k * (1-p)^(n-k)

In this case, n = 30 (total number of questions), k = 18 (number of correct answers), and p = 0.5 (probability of getting a question correct by guessing).

Plugging in the values into the formula, we get:

P(X = 18) = C(30,18) * 0.5^18 * 0.5^12

Using a calculator or statistical software, we can compute this probability to be approximately 0.285.

Therefore, the correct answer is B) 0.285.