Question 278277: In a small class of 10 students, 3 did not do their homework. The professor selects half of the class to present solutions to homework problems on the board, and records how many of those selected did not do their homework. What is the expected number who did not do homework?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! In a small class of 10 students, 3 did not do their homework.
The professor selects half of the class to present solutions to homework problems on the board, and records how many of those selected did not do their homework. What is the expected number who did not do homework?
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Random # values: 0,1,2,3,
Corresponding Probabilities:
P(x = 0) = binompdf(5,0.3,0) = 0.1681
P(x= 1) = binompdf(5,0.3,1) = 0.3602
P(x=2) = binompdf(5,0.3,2)= 0.3087
P(x=3) = binompdf(5,0.3,3)= 0.1323
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Procedure:
Multiply each random number value by its probability.
Add the results of those products to find the expected number.
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Cheers,
stan H.
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