Oops - what I meant to say was "What if my NEGATIVELY skewed data all have negative values, say from -1 to -7? Does the same logic/procedure still hold?"
Because I cannot take the log of a negative number and instead take the absolute value of those numbers, I'll have positively skewed data. And I could simply take the log of those and proceed? DW --- Paul R Swank <[EMAIL PROTECTED]> wrote: > You can't take the log of a negative number. You > need to take an absolute > valute or other convert the number of non-negative. > > Paul R. Swank, Ph.D. > Professor, Developmental Pediatrics > Medical School > UT Health Science Center at Houston > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > Behalf Of Dianne Worth > Sent: Wednesday, June 18, 2003 1:02 PM > To: [EMAIL PROTECTED] > Subject: Logs of nonnormal distributions? > > > It is my understanding that if the data > distribution is positively skewed > , one can take a log of the data. If it's > negatively skewed, one should > 'flip' it by adding 1 to the largest value, and a > series of steps that are > probably best explained as follows: > Original values are 1-8. > Add 1 to 8 = 9. > FLIPX=9-X > LOGFLIPX=LOG(FLIPX) > LOGX=.903089 - LOGFLIPX > where .903089 is the log of the original largest > value (8). > > My question: What if my positively skewed data all > have negative values, > say from -1 to -7? Does the same logic/procedure > still hold? > Thanks, > DW > > > ---------------------------------------------------------------------------- >================================================================= > Instructions for joining and leaving this list, > remarks about the > problem of INAPPROPRIATE MESSAGES, and archives are > available at: > . http://jse.stat.ncsu.edu/ > . > ================================================================= __________________________________ Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
