Question

On Excel, A multiple choice test has 30 problems, and 4 choices for each problem. A student taking the test does not know the correct answer for any of the problems and guesses each answer. What is the probability that the student will answer at least 10 questions correctly?

Answer 1

Solution:

Given : A multiple choice test has 30 problems , thus n = number of trials = 30

4 choices for each problem. thus p = probability of correct answer = 1 / 4 = 0.25

We have to find:

the probability that the student will answer at least 10 questions correctly

That is:

thus use following excel command to find the probability.

=BINOM.DIST.RANGE( n , p , lower limit x , upper limit of x)

Since we have to find probability of at least 10, so lower limit would be 10 and upper limit would be value n = 30.

Thus we get:

=BINOM.DIST.RANGE(30,0.25,10,30)

=0.196593

=0.1966

thus