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From |
"Buzz Burhans" <buzzb3@earthlink.net> |

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

Subject |
RE: st: how to find the integral for a portion of a normal distribution. |

Date |
Mon, 3 May 2010 22:52:44 -0600 |

This gets me what I want, but there should be an easier way to express this as 2 equations? clear drawnorm x , means(2.05) sds(1.74) n(100000) clear sort x egen lowresponse = total(x) if _n < (100000*.273) egen highresponse = total(x) if _n >= (100000*.273) l in 1/50 l in -60/l Buzz Burhans, Ph.D. Dairy-Tech Group So. Albany, VT / Twin Falls ID Phone: 802-755-6842 Cell: 208-320-0829 Fax VT: 802-755-6842 Fax ID: 208-735-1289 Email: buzzb3@earthlink.net -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of David Muller Sent: Monday, May 03, 2010 10:26 PM To: statalist@hsphsun2.harvard.edu Subject: Re: st: how to find the integral for a portion of a normal distribution. To expand upon Michael's suggestion, -display normal((1 - 2.05)/1.74)- will give you the proportion of responses <=1, and -display 1 - normal((1 - 2.05)/1.74)- will give you the proportion of responses >=1. Note that assuming this normal model for your response you would expect a little over 10% of your responses to be less than 0, which indicates a problem with your assumption if your response is strictly positive. David On Tue, May 4, 2010 at 2:01 PM, Hollis,Michael E <mhollis@mwdh2o.com> wrote: > ...you'll then be able to use the standard normal distribution with mean > zero and unit variance. > > Sent from my iPhone > > On May 3, 2010, at 8:49 PM, "Buzz Burhans" <buzzb3@earthlink.net> wrote: > >> Doesn't your suggestion fit only if the curve is standard normal?, i.e. >> mean >> 0, SD 1? >> >> Perhaps my use of integral is incorrect; what I want is the area under the >> curve of a normal distribution, mean 2.05, sd 1.75 for the portion >= >> threshold =1, and then the portion < 1 >> >> Buzz >> >> >> statalist@hsphsun2.harvard.edu] On Behalf Of Hollis,Michael E >> Sent: Monday, May 03, 2010 9:36 PM >> To: statalist@hsphsun2.harvard.edu >> Subject: Re: st: how to find the integral for a portion of a normal >> distribution. >> >> I may be missing something here, but can't you simply use the normal >> distribution with mean=proportion z >= some threshold, q=1-p and >> variance p(1-p)/n? No integration involved. >> >> As I said, I might be missing something! >> >> Sent from my iPhone >> >> .ucla.edu/stat/stata/ >> >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/statalist/faq >> * http://www.ats.ucla.edu/stat/stata/ > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: how to find the integral for a portion of a normal distribution.***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**References**:**Re: st: how to find the integral for a portion of a normal distribution.***From:*David Muller <davidmull@gmail.com>

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