Question

Assume that random guesses are made for eight multiple choice questions on an SAT​ test, so that there are n=8 ​trials, each with probability of success​ (correct) given by p=0.2. Find the indicated probability for the number of correct answers.

Find the probability that the number x of correct answers is fewer than 4.

Answer 1

p = 0.2

n = 8

x = 4

P(X < 4) = BINOM.DIST(3,8,0.2,TRUE) [Excel formula ]

= 0.9437

Probability = 0.9437