Question

A test consists of 10 multiple choice questions, each with five possible answers, one of which is correct. To pass the test a student must get 60% or better on the test. If a student randomly guesses, what is the probability that the student will pass the test? Please show work

Answer 1

Sample size = n = 10

Probability of correct answers = p = 1/5 = 0.2

To pass the test a student must get 60% or better on the test.

That is 10*0.60 = 6

That is we have to find P(X 6)

P(X 6) = P(6 X 10) = 1 - P( 0 X 5)

Using Ti-84 calculator.

P(X 6) = 1-binomcdf(10,0.2,5)

P(X 6) = 0.0064

The probability that the student will pass the test is 0.0064