linear correlation?

Hello 

dechao wang wrote:

Hi, I have checked statistic textbooks about
correlations, but I am still not sure the correlation
analysis with different units, for example,

x1<-c(1,  2,  3,   100, 200, 300)
x2<-c(1.1,2.8,3.3, 108, 209, 303)
the unit of the first 3 numbers is cm
the unit of the last 3 numbers is kg

cor(x1,x2)=0.999655

Can I explain the correlation coefficient as normal in
which all numbers have the same unit?

No, that will give different results. The unit must be the same for all
values. Which unit isn't important, but it must be the same

OOPS - I apologize, I misread the question, I understood the OP to be
saying that x1 was in cm and x2 was in kg. 

What on earth would a correlation mean between two vectors, each of which
is made up of two entirely different measures? (These aren't just
different units, they're measures of entirely different phenomena.)


----------------------------------------------------------------------
Andrew J Perrin - andrew_perrin at unc.edu - http://www.unc.edu/~aperrin
 Assistant Professor of Sociology, U of North Carolina, Chapel Hill
      269 Hamilton Hall, CB#3210, Chapel Hill, NC 27599-3210 USA




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