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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Anti-Spam Code: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by viggozhang[/i] [br]Origin Ver. and Service Release (Select Help-->About Origin): Operating System: Hey guys, an urgent question here about log Gaussian fitting for your kind help. The case is like this, Quite some data points. At first I take "ln" of the variable "x", and then plot "f(x)" vs "t=ln(x)" on a linear scale, i.e. horizontal axis of t, and vertical axis of f(x). Afterwards, I fitted the curve by Gaussian f(x)=y0+2A*exp{-2(x-u)^2/w^2}/w(2Pi)^2 in Origin. (I noticed the definition difference of "w" in Origin, and which is not what I wanna ask.) So here come my questions, 1. In this case, if the fitting is quite Ok, does it mean that I can call my data distribution "Log Gaussian"? 2. I think I made a mistake in the above-mentioned fitting procedure. So I gave it a second try: I multiplied my "f(x)" by "x" first, and then did exactly the same thing for fitting "x*f(x)" vs "t=ln(x)". The fitting is quite Ok. I think I can only call this a log Gaussian fitting and then use the corrected expressions for "u" and "w" in stead of using "u" and "w" values directly. I know this is a relavtiely simple question, but I am really getting killed by this problem =.= maybe not smart enough... so, SOS~~ [/quote]   Check here to include your profile signature. Check here to subscribe to this topic.