probability of guessing four correct out 20 multiple choices

If a student randomly guesses at 20 multiple-choice questions, what is the probability that the student gets exactly four correct? Each question has four possible choices. (Enter your answer in decimal format. Answer should have two decimal positions.)

Solution Preview

Let X be the number of correct answers. X has the binomial distribution with n = 20 trials and success probability p = 0.25 (1 out 4 possible choices ...

Solution Summary

The solution explains how to calculate the probability of guessing four correct out 20 multiple choices, which follows a binomial distribution.

... randomly guesses at 20 multiple-choice questions, find the probability that the student gets exactly four correct. Each question has four possible choices. ...

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... it would be unusual for a student to pass the exam by guessing and getting ... Normal Probabilities. ...Probability for X > X Value 59.5 Z Value 9.875 P(X>59.5) 0.0000 ...

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... b. Would it be unusual for a student to pass by guessing and getting at least ... Normal Probabilities. ...Probability for X > X Value 70 Z Value 2.56 P(X>70) 0.0052. ...