Question

A test has multiple choice questions with 5 choices for each answer; only one answer is correct for each question. Suppose a student guesses the answer to each question. Assuming the guesses are independent, find the probability that the student will not guess correctly on any one question.

Answer 1

First you have to define perimeters of Binomial distribution.

n - how many trials/questions do you have
p - probability guessing right answer to each question
x - how many successes do you expect.
Assuming the 6 questions are independent,
n=6 (questions)
p=probability of guessing the right answer (1/5)
x=exactly the number of successes over the 6 questions (2).

Look up the appendix table, or the Excel function to calculate the probability.