Question 204453This question is from textbook elementary statistics
: Find these probabillities for a sample of 20 teenagers if 70% of them had compact disk players by the age of 16. Round to three decimal places, example 0.123.
a. At least 14 had CD players.
b. Exactly 9 had CD players.
c. More than 17 had CD players.
This question is from textbook elementary statistics
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Find these probabillities for a sample of 20 teenagers if 70% of them had compact disk players by the age of 16. Round to three decimal places, example 0.123.
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Hopefully you have software or a calculator to work these binomial problems.
If not you will have to use z-scores and a Table of z-values.
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a. At least 14 had CD players.
P(14 < x <= 20) = 1 - binomcdf(20,0.7,13) = 0.6080
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b. Exactly 9 had CD players.
P(x = 9) = binompdf(20,0.7,9) = 0.0120
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c. More than 17 had CD players.
P(18 <= x <=20) = 1 - binomcdf(20,0.7,17) = 0.03548
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Cheers,
Stan H.
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