Question

A student takes an 18-question, multiple-choice exam with five choices for each question and guesses on each question. Assume the variable is binomial. Part: 0 / 20 of 2 Parts Complete Part 1 of 2 Find the probability of guessing at least 9 out of 18 correctly. Round the answer to at least four decimal places.

Answer 1

Answer:

Probability of getting at least 9 out of 18 correctly is 0.0043

Step-by-step explanation:

We have

n = 18

p = 1/5 for correct answer

q = 4/5 for wrong answer

P( 9 $\leq$ X $\leq$ 18) = 1 - P(0 $\leq$ X$\leq$ 8)

                       = 1 -  0.9957

                         =0.0043