Question 807476
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What do "flase" and "qhat" mean?  Which is to say, please have the common courtesy to check your post for obvious spelling and other errors BEFORE you push the send button.


In the meantime:


The probability of *[tex \Large k] successes in *[tex \Large n] trials where *[tex \Large p] is the probability of success on any given trial is given by:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ P(n;k,p)\ =\ {{n}\choose{k}}\left(p\right)^k\left(1\,-\,p\right)^{n\,-\,k}]


Where *[tex \LARGE {{n}\choose{k}}] is the number of combinations of *[tex \Large n] things taken *[tex \Large k] at a time and is calculated by *[tex \Large \frac{n!}{k!(n\,-\,k)!}]


"At least 3" means the probability of exactly 3 plus exactly 4, plus exactly 5, ... and so on.  A much simpler calculation that gets you to the same place is 1 minus the probabilities of exactly zero, plus exactly 1, plus exactly 2.  So:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ P(10;\geq 3,0.5)\ =\ 1\ -\ \sum_{k=0}^2\,{{10}\choose{k}}\left(0.5\right)^k\left(0.5\right)^{10\,-\,k}]


Happy calculating.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
<font face="Math1" size="+2">Egw to Beta kai to Sigma</font>
My calculator said it, I believe it, that settles it
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