SOLUTION: a student takes a 22 question multiple choice exam with four choices for each question and guesses on each question. Assume the variable is binomial find the probability of guessin
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Question 1127552: a student takes a 22 question multiple choice exam with four choices for each question and guesses on each question. Assume the variable is binomial find the probability of guessing at least 7 out of 22 correctly Answer by solver91311(24713) (Show Source):
You need the probability of seven successes out of 22 trials, plus eight successes out of 22 trials, plus nine...and so on up to 22 successes out of 22 trials.
The probability of successes out of trials where the probability of success on any given trial is is given by:
So you need the sum:
For at least 7 out of 22, you will have a sum with 16 terms. The following sum, which gives you the same result only requires calculating 8 terms:
Make sure your calculator has fresh batteries.
John
My calculator said it, I believe it, that settles it
