>> The scale function will return the mean and sd of the data. By default. Read ?scale.
Mark. Noah Silverman-3 wrote: > > I think I just answered my own question. > > The scale function will return the mean and sd of the data. > > So the process is fairly simple. > scale training data varaible > note mean and sd from the scale > then manually scale the test data using the mean and sd from the > training data. > > That should make sure that a value is transformed the same regardless of > which data set it is in. > > Do I have this correct, or can anybody contribute any more to the concept? > > Thanks! > > > -- > Noah > > On 9/11/09 1:10 PM, Noah Silverman wrote: >> Hi, >> >> Is there an alternative to the scale function where I can specify my >> own mean and standard deviation? >> >> I've come across an interesting issue where this would help. >> >> I'm training and testing on completely different sets of data. The >> testing set is smaller than the training set. >> >> Using the standard scale function of R seems to introduce some error. >> Since it scales data WITHIN the set, it may scale the same number to >> different value since the range in the training and testing set may be >> different. >> >> My thought was to scale the larger training set of data, then use the >> mean and SD of the training data to scale the testing data according >> to the same parameters. That way a number will transform to the same >> result regardless of whether it is in the training or testing set. >> >> I can't be the first one to have looked at this. Does anyone know of >> a function in R or if there is a scale alternative where I can control >> the parameters? >> >> Thanks! >> >> -- >> Noah >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > > -- View this message in context: http://www.nabble.com/Alternative-to-Scale-Function--tp25407625p25408289.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
