SOLUTION: in the past no shows were 20% of the people registered in a race. there are 225 registered this year. what is the probability of a. 220 no-shows?

Question 274526: in the past no shows were 20% of the people registered in a race. there are 225 registered this year. what is the probability of a. 220 no-shows?
B. 50 or less no-shows?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
in the past no shows were 20% of the people registered in a race.
there are 225 registered this year.
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Binomial problem with n = 225 ; p = 0.2
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what is the probability of
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a. 220 no-shows?
P(x = 220) = 225C220(0.2)^220(0.8)^5 = binompdf(225,0.2,220)
My calculator says the answer is zero to 8 decimal places.
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B. 50 or less no-shows?
P(0<= x <=50) = binomcdf(225,0.2,50) = 0.8211
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Cheers,
Stan H.
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