Question 441087
The question reads: A university has 10,000 students of which 4,000 are male and 6,000 are female. If a class of 30 students is chosen at random from the university population, find the mean and standard deviation of the number of male students.
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P(male) = 4/10 = 2/5
n = 30
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mean = np = (2/5)30 = 12
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std = sqrt(npq) = sqrt(12*(3/5)) = 2.6833
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I agree with your answers.
Cheers,
Stan H.
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After using the formula for binomial distribution mean (np) and standard deviation (square root of np(1-p), I came up with the answer... 
mean= 12
standard deviation = 2.68 
I am confused when to use which equation so I was hoping you could verify my answer.