[SOLVED] binomial distribution problem

n=7,r=3,p=0.25
Pr= 7!/3!(7-3)!=1(0.25)^3(1-0.25)^4 =0.004943848.
Why is this answer wrong ?
The correct answer is 0.173035

Quote:

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Originally Posted by chaosx

n=7,r=3,p=0.25
Pr= 7!/3!(7-3)!=1(0.25)^3(1-0.25)^4 =0.004943848.
Why is this answer wrong ?
The correct answer is 0.173035

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For the Binomial distribution:



so in this case:



RonL