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A student takes a 40-question multiple-choice exam but did not study and randomly guesses each answer.
Each question has three possible choices for the answer. Find the probability that the student guesses
more than 75% of the questions correctly. (Round your answer to three decimal places.
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This is a binomial experiment with n= 40 trials and p= 1/3 = 0.333333333 probability
of the individual success for each question, separately.
They want you determine the probability of 31 or more successes(correct answers).
(More than 75% correct answers of 40 questions means 31 or more correct answers).
You can use regular calculator TI-83/84 with standard function binomcdf, or Excel function BINOM.DIST,
or free of charge online calculator https://stattrek.com/online-calculator/binomial.aspx
With only three decimals, the ANSWER is P = 0.000.
Solved.
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This request to round with 3 decimal places does not work in this problem and is inapplicable.
A real probability is about 0.0000000018 (obtained by using BINOM.DIST in Excel).