SOLUTION: 2. One out of 10 students [10%] don’t buy a book for their statistics class. In a class of 25 students [assume these students are a random selection from the population of all stud

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Question 267238: 2. One out of 10 students [10%] don’t buy a book for their statistics class. In a class of 25 students [assume these students are a random selection from the population of all students who might take this course], calculate the following probabilities.
a. P(3 or fewer students don’t buy a book) =
b. P(exactly 3 students don’t buy a book) =
c. P(exactly 5 students did buy a book) =

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
One out of 10 students [10%] don’t buy a book for their statistics class. In a class of 25 students [assume these students are a random selection from the population of all students who might take this course], calculate the following probabilities.
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A binomial problem with n= 25 ; p = 0.1
a. P(3 or fewer students don’t buy a book) = binomcdf(25,0.1,3) = 0.7636
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b. P(exactly 3 students don’t buy a book) = binompdf(25,0.1,3) = 0.2265
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c. P(exactly 5 students did buy a book) = binompdf(25,0.99,5)
= 25C5(0.99)^5(0.1)^20 = 5.053x10^-16
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Cheers,
Stan H.