SOLUTION: One question with 3 answers: dont need to show work. Thank you! Twenty percent of American households own three or more cars. A random sample of 100 American households is sele

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Question 846511: One question with 3 answers: dont need to show work. Thank you!
Twenty percent of American households own three or more cars. A random sample of 100 American households is selected. Let X be the number of households selected that own three or more cars.
The standard deviation of X is ______
The mean of X is ____
The probability that at least 28 of the households selected own at least three or more cars is _______



Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

p = .20,  n = 100

mean = .20%2A100+=+20

variance =s .20%2A.80%2A100+=+16

SD = sqrt%2816%29 = 4

P(x ≥ 28) = 1 - binomcdf(n, p, largest x-value) = 1 - binomcdf(100, .20,+highlight_green%2827%29)= 1 -  .9658 = .0342  0r 3.42 %