Re: 3rd degree polynom curve fitting, correlation needed
Matti Overmark wrote: I have fitted a 3 rd degree curve to a sample (least square method), and I want to compare this particular R2 with that of a (similarily) fitted 2 degree polynom. I can assure you that the 3rd degree polynomial will fit as well or better than the 2nd degree polynomial, as measured by R-squared. If you want a statistical test to test the hypothesis that the 3rd degree model yields a significantly better fit compared to the second degree model, then you should do an extra-sums-of-squares test, as explained in the fine textbook by Draper and Smith Applied Regression Analysis. I want to see which of the two models is the best. Any suggestion of a good book? A plot would work just fine, if you want to see how the models fit. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] It's nothing until I call it! -- Bill Klem, NL Umpire When you get the choice to sit it out or dance, I hope you dance -- Lee Ann Womack = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Confidence region plots
carl lee wrote: Hello, there: I am looking for software or programs that has procedure for drawing confidence region for bivariate cases, such as Youden Plot. I am not aware that the commonly used software such as Minitab, SPSS or SAS has procedures for this. If anyone has such a program or happens to know any resource, I would appreciate for such information. I am not sure what a Youden Plot is, however, bivariate normal confidence ellipses are not hard to draw in SAS, particularly if you use the procedure outlined in Jackson, J. E. (1991) "A User's Guide To Principal Components", John Wiley and Sons, New York, Chapter 15. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] "It's nothing until I call it!" -- Bill Klem, NL Umpire "Those black-eyed peas tasted all right to me" -- Dixie Chicks = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Paired t test Question
"Andrew L." wrote: I am anlaysing some data and want to administer a paired t test. Although i can perform the test, i am not totally familiar with the t-test. Can anyone tell me whether the test relies on having a large number of samples, or whether i can still realte an accurate answer from n=4 (n= number of participants). Also, does anyone know what the F stands for - i think it means F-test. What is this test designed to show. I think you should definitely get a basic introductory book on statistics and brush up on your statistical knowledge. In regards to your specific questions, the accuracy of your results doesn't really depend on the sample size, but the precision does. Your comparison of the means (You do want to compare means, don't you? You didn't actually say that...) will not be very precise with just 4 samples. F may stand for an F-test and it may stand for a lot of other things; I don't normally associate doing a F-test with a paired t-test. So I would advise, based upon your questions, don't just mechanically crank a paired t-test through whatever software you have ... sit down with someone who knows statistics and explain your entire problem to him or her, and find out if a paired t-test is the right thing to do, and how a sample size of 4 affects your comparison of the means. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] "It's nothing until I call it!" -- Bill Klem, NL Umpire "Those black-eyed peas tasted all right to me" -- Dixie Chicks = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Patenting a statistical innovation
Warren Sarle wrote: In article [EMAIL PROTECTED], Paige Miller [EMAIL PROTECTED] writes: If it so happens that while I am in the employ of a certain company, I invent some new algorithm, then my company has a vested interest in making sure that the algorithm remains its property and that no one else uses it, especially a competitor. That would be perfectly reasonable. Unfortunately, patent law doesn't work that way. You cannot patent an algorithm per se. But anybody can patent applications of the algorithm that you invented. You could end up having to pay royalties to somebody else for using your own algorithm. The law is insane. It doesn't make sense to me either, but that is exactly what we have done. We have patented a mathematical procedure as applied to chemical manufacturing. If someone else wanted to patent the exact same mathematical procedure as applied to veterinary care, I suppose they could. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] "It's nothing until I call it!" -- Bill Klem, NL Umpire "Those black-eyed peas tasted all right to me" -- Dixie Chicks = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Guidence requested
Rahat Bokhari wrote: Hi. Arelationship between two variables X and Y is measured in terms of g = 0.19, using technique "Partial Least Square" in a paper. My question is "What does 'g' explain". Is it "standarized mean difference". You'll need to provide more details. I use Partial Least Squares occasionally, but I have really never seen it used with only 2 variables, one X and one Y. Usually it is used when there are multiple X and possibly multiple Y. In the case where Partial Least Squares is used on one X and one Y, you ought to get the same answer as Ordinary Least Squares, and I am not used to seeing any output of either procedure being labelled g. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] "It's nothing until I call it!" -- Bill Klem, NL Umpire "Those black-eyed peas tasted all right to me" -- Dixie Chicks = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Patenting a statistical innovation
dennis roberts wrote: just think about all the software packages ... and what they would HAVE (or HAD) to do if these routines were "patented" ... sure, i see "inventing" some algorithm as being a highly creative act and usually, if it is of value, the person(s) developing it will gain fame (ha ha) and some pr ... but, not quite in the same genre of developing a process for extracting some enzyme from a substance ... using a particular piece of equipment specially developed for that purpose i hope we don't see a trend IN this direction ... If it so happens that while I am in the employ of a certain company, I invent some new algorithm, then my company has a vested interest in making sure that the algorithm remains its property and that no one else uses it, especially a competitor. Thus, it is advantageous for my employer to patent such inventions. In this view, mathematical inventions are no different than mechanical, chemical or other inventions. -- Paige Miller Eastman Kodak Company [EMAIL PROTECTED] "It's nothing until I call it!" -- Bill Klem, NL Umpire "Those black-eyed peas tasted all right to me" -- Dixie Chicks = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
