There was a question on the test with the following information (binomial distribution)(adsbygoogle = window.adsbygoogle || []).push({});

n=10

p=.2

Find the probability that X is :

a. At least 3

b. At most 3

For part a I did P(X>=3)=1-P(X<=2)

For part b I did P(X<=3) :

[itex] \sum_{x=0}^3 perm(n, x)*p^x*(1-p)^(n-x)[/itex]

The last part is (1-p)^(n-x)

For part b, I got an answer that is greater than 1, what did I do wrong?

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# Probability and binomial distribution question

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