why do we do a principal component analysis?
965098
I believe this methodological approach compares data from observation of natural phenomena, rather than controlled experiments, to make a credible claim. It may not be feasible, legal, or ethical to do certain experiments, so you basically have to look at what's happening in nature to infer conclusions. Maybe try looking up 'natural experiment' or 'comparative method?'
113822
A 100 by 100 matrix has 100 eigenvectors. I would use some software to do this. This is too hard to do by hand. Buy the student version of MATLAB for example. You might be able to find some free software on the internet as well.
327573
Let's see...it's desireable because it's likely to be a lot different than your starting material and your derivatizing agent - this gives you confidence that you actually made a derivative and are not just measuring the m.p. of either your unreacted agent or your starting material.  We used this a lot when I took a class called the Analysis of Organic Unkowns.  No instruments were allowed.
545935
http://en.wikipedia.org/wiki/Eigenvalue\n\nI read through this and it made more sense to me this time than it ever has.  You can think of the solutions to a problem as vectors that point in a certain specific direction.  An eigenvector is a solution vector that points along the same direction but has a different scale length compared to the original vector.  That scale length is the eigenvalue/s.
1174451
Which norm? There are many different norms that are used for matrices! Look up the uncertainty principle.
377891
I think statistics has a higher chance of being relevant. It's usual to be able to analyze studies in any subject.
123406
Try Chi square testing, it starts out complicated but once you understand it, it is way faster than punnett squares! You can find all kinds of stuff about it on the internet, it's a statistical analysis.
929935
variations matter greatly in interpreting data.  Something might seem like it is returning significantly different results than the control but stat evaluation may show that the variations are minimal at best
579637
Basically it's a complex mathematical process to process the vibration response data obtained from siesmic excitation of an oil field to characterize the field in terms of parameters understandable to the analyst (e.g., porosity and impedance). See the ref.
917786
most statistics follow a pattern, whether it be linear, quadratic, or whatever. Once you have enough data to establish a pattern, you can accurately predict the remainder of the line.\n\nFor instance, you have a line that looks to be half a parabola. Once it starts going back up, you can be pretty certain of where it's going to be.
279951
It'd help to have  more detailed information. \nWhat does it mean that "pixels are independent?" \nAssuming that pixels are multivariate random variables, having n possible values for each color, the intensity of each component surely is correlated with that of adjacent pixels, I'd suppose.\nNow, what do you mean by "compression result"?\nPut more info. Your problem seems nice to tackle
598449
Look what i have study in Computer Vision .. that there is steps u do to recognise the body or the shapes generally in computer vision\n\nand this vision helps in many things like defence in countries and radars \n\nso \n\n1- detect the object Ur looking at .. and u can separate it or segment it \n\n2- recognition of this object .. this recognition is by feature Extraction from that body\n\nthis features r many .. like FFT "Fast Fourier Transform"\nMean,Median,Variance....etc\n\nwhatever Ur feature is .. u make this feature to separate groups from each other .. like separating Gray scale colours as  An example .. or in medical Image .. to recognise the damaged tissue by search about high destiny colours in the image\n\n3- after features Extraction u have to Classify ur Groups \nlike belong each Shape to its group .. till u find ur wanted shape\n\nafter recognition .. u have to do decision\n\nlike in Radars .. if u detect an plane in Ur country air field .. it inform it to out or hit it .. this is the decision\nor in auto driving Cars based on Computer vision\nby recognition people from cars and to talk the decision to stop or move or turn \n\n\ni hope i could helped u man \n\nif u found ur answer give me the ten points :))
462795
I guess it is because to interpret something you need a baseline or standard to compare your result with ... finding such a standard would be why you would use a database
448807
Also, don't forget the huge field of use for statistics in botany - probability of measurements on one plant being significantly more or less than on another plant. And some plants show an architecture that is 4-sided (e.g. the mint family), while others show some other arrangement not based on 4 sides.
466068
If you are referring to validity, do a principal components analysis.  Reliability use Cronbach's alpha.  Cross reference your results from PCA with Cluster Analysis.  I am a sas user so I only no the code for sas which is:\n\nproc factor data=females\nsimple\nmethod=prin\npriors=one\nmineigen=1\nscree\nrotate=varimax\nround\nflag=.5;\nvar rate1-rate10;\nrun;\n\nRobert DeVellis; Scale Development: Theory and Application 2nd edition.
87093
Job Analysis data can be used to specify some of the major job requirements like educational requirements.\n\nBased on these the recruitment activity can be focussed on those institutions working in those areas
356040
elementary mode analysis Is also known as extreem path way analysis. It defines the limiting bondaries of the operation of a metabolic network. The normal approach is to use singular value decomposition to determine the constraints of a metabolic network.\n\nTo be honest its a bit over rated since all it does is define the feasable space of operation of a cell. You have to use other principles such as cyberbnetics (maximise growth rate and then use linear programming) or kinetic modeling to determine the expected operation of a cell. \n\nTry a search for Palson - but dont cite or talk to him because he is an arrogant self promoting w****r who doesnt cite competing groups work.