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From |
"Carlo Lazzaro" <carlo.lazzaro@tin.it> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
R: st: probability mass function for a binomial distribution |

Date |
Sun, 29 Jun 2008 19:10:44 +0200 |

Dear Nick, thanks a lot for making it simpler than I was figured out it to be. I agree with you about the theoretical endless row of defined functions which may be included in a statistical package: a reasonable compromise between users'neeeds and their statistical background is the way to go for delivering an effective and efficient software. Kind Regards, Carlo -----Messaggio originale----- Da: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di Nick Cox Inviato: domenica 29 giugno 2008 17.27 A: statalist@hsphsun2.harvard.edu Oggetto: RE: st: probability mass function for a binomial distribution What is available as a defined function shows up a trade-off problem. It wouldn't be difficult to define a thousand functions, but then some people might complain about the complexity of the list and the difficulty of finding a solution. Otherwise put, I guess the answer to Carlo's question is that Stata users -- unlike spreadsheet users, it seems --- are paid the compliment of knowing enough statistics to work this out from first principles: gen double bmp = p^k * (1 - p)^(20 - k) * comb(20, k) Note in passing two other details: I prefer to use -double-s here. Putting constants into variables isn't necessary: gen double bmp = 0.2^k * 0.8^(20 - k) * comb(20, k) In cases like this the advantage of a canned function over a one-line solution using another canned function would be pretty small. Nick n.j.cox@durham.ac.uk [previous message deleted to avoid Buffer overrun warning] * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**RE: st: probability mass function for a binomial distribution***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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