Thanks Jason. Here is a related reply, which I am forwarding to the list. -- John
From: [EMAIL PROTECTED] (Jim Jaccard) Newsgroups: comp.soft-sys.stat.spss John - One of the more common indices of variability used that is reasonably outlier resistant and that often is reported in conjunction with the median is called the Median Absolute Deviation statistic or MAD. A common form of MAD is to subtract the median from each score, then take the absolute value of these deviation scores and then take the median of the absolute deviations. The index tells you, on average (in a median sense) how much scores deviate from the median. The are other forms of MAD as well. Rand Wilcox has written several books on robust statistics that describe this index, statistical tests associated with it, and other indices of variability that are outlier resistant. I recommend you check out his books and work. You can get the value of MAD in SPSS in the explore program. Jim . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
