Path: news.mathworks.com!not-for-mail From: "John D'Errico" <woodchips@rochester.rr.com> Newsgroups: comp.soft-sys.matlab Subject: Re: Limiting case of an exponential distribution Date: Sat, 10 Jan 2009 14:23:01 +0000 (UTC) Organization: John D'Errico (1-3LEW5R) Lines: 39 Message-ID: <gkab05$b8e$1@fred.mathworks.com> References: <5e3bfffd-9cf6-417e-8c92-fe40feedcd71@o40g2000prn.googlegroups.com> Reply-To: "John D'Errico" <woodchips@rochester.rr.com> NNTP-Posting-Host: webapp-02-blr.mathworks.com Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8bit X-Trace: fred.mathworks.com 1231597381 11534 172.30.248.37 (10 Jan 2009 14:23:01 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sat, 10 Jan 2009 14:23:01 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 869215 Xref: news.mathworks.com comp.soft-sys.matlab:510765 Adshak <adshaikh.hipnet@googlemail.com> wrote in message <5e3bfffd-9cf6-417e-8c92-fe40feedcd71@o40g2000prn.googlegroups.com>... > Dear All, > > I have an exponential distribution curve which is given by: > > t = (0.0001:0.0001:15); > z = (15625000/567) .*t.^9.*exp(-10.*t); > > figure; > plot(t,z); > > > Now I am told that the limiting case of this exponential distribution > is a gaussian curve. > > I am not very good at statistics. > > Can somebody kindly explain to me the significane of the limiting case > of this exponential curve and why it is a gaussian curve....and how do > I find anf fit this gaussian curve to this exponential curve (a few > matlab commands might very helpful). > > I have tried googling 'limiting case of exponential distribution' but > didnt find any good explanation. > > Thanks in advance. Perhaps the problem is this is not an exponential distribution at all. Assuming that you are trying to plot the pdf, this is a: http://en.wikipedia.org/wiki/Gamma_distribution If you wish to approximate this with a normal distribution, then you could most simply just use a normal with the same mean and variance as this gamma. John