search for: chemometricians

Valued R-community. Please let me make you aware of a job opening with focus on Statistics at BASF in Shanghai: We are the world's leading chemical company because we offer intelligent solutions for our customers and for a sustainable future. We link and develop people with diverse talents all over the world. For you, this means a variety of ways to advance. Not only your performance but

Firstly hi to everyone on the list, I am new to this list ans also R so please forgive the simplicity of my questions over the next few months. I have version R 1.9.1 and want to perform z-scoring for a benchmarking procedure. I have tried to install Henrik Bengtsson's R.classes bundle (http://www.maths.lth.se/help/R/R.classes). I have downloaded the .zip file and placed the relevant folders

Apologies to the listing, the problem was with the data set and not the code Thanks Michael Griffiths, Ph.D. Chemometrician Training, Quality and Statistics Group LGC Limited Queens Road Teddington Middlesex, TW11 0LY, UK Tel: +44 (0)20 8943 7352 Fax: +44 (0)20 8943 2767 e-mail: michael.griffiths at lgc.co.uk >>> "Michael Griffiths" <Michael.Griffiths at lgc.co.uk>

...comp(x) Error in princomp(x) : covariance matrix is not non-negative definite > Seeing this behavior on the matrix I tried, I hastily concluded that princomp was not suitable for this type (as similar functions are in many other software packages which are written for psychologists but not for chemometricians). ======================================================= However, the problem is not with the design of princomp in general, but with a little check it performs inside, which can have problems with roundoff: if (any(edc$values < 0)) stop("covariance matrix is not non-negativ...

...comp(x) Error in princomp(x) : covariance matrix is not non-negative definite > Seeing this behavior on the matrix I tried, I hastily concluded that princomp was not suitable for this type (as similar functions are in many other software packages which are written for psychologists but not for chemometricians). ======================================================= However, the problem is not with the design of princomp in general, but with a little check it performs inside, which can have problems with roundoff: if (any(edc$values < 0)) stop("covariance matrix is not non-negativ...

I wholeheartedly agree. Maybe in time the list will divide into two whereby 'apparantly' simple questions will be answered without a curt rebuke! I too am now signing off the list and will bury my head in a manual ot two. As a last comment; everyone has to start the learning process somewhere and lets face it, with a deadline looming and what appears to be an insurmaountable question

Before I receive a barrage of 'try looking in the help file' messages, I have and to no avail. For a new user of R I would like to point out that in order to be able to use the help files/manuals effectively one must know the correct question and that only comes with using R! Could someone please direct me to why I keep getting the following error message "Error: subscript out of

Dear R gurus, I have some climatic data for a region of the world. They are monthly averages 1950 -2000 of precipitation (12 months), minimum temperature (12 months), maximum temperature (12 months). I have scaled them to 2 km x 2km cells, and I have around 75,000 cells. I need to feed them into a statistical model as co-variates, to use them to predict a response variable. The climatic