SOLUTION: in one city, 21% of adults smoke. in groups of size 130 adults, what is the variance of the number that smoke?

SOLUTION: in one city, 21% of adults smoke. in groups of size 130 adults, what is the variance of the number that smoke?

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Question 624881: in one city, 21% of adults smoke. in groups of size 130 adults, what is the variance of the number that smoke?
Answer by oscargut(2103) (Show Source): You can put this solution on YOUR website!
Solution:
we know: n = 130 and p=0.21
Variance = np(1-p)= 130(0.21)(0.79) = 21.567
Answer: 21.567
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