Robert, I don't think I understand your argument... Are you saying that the "descriptive statistic" should be invariant over scale?
Anyway, more to the point... the "add one" is an old argument based on the notion of "real limits." Suppose the range of scores is 50 to 89. It was argued that 50 really goes down to 49.5 and 89 really goes up to 89.5. Thus the range was defined as 89.5 - 49.5... thus the additional one unit... Personally, I don't subscribe to this position... It assumes that the low score is always toward the low end of its value and that the upper value is always toward the high end of its value... Sort of a maximum range... I prefer not including the additional one unit... Bill __________________________________________________________________________ William B. Ware, Professor and Chair Educational Psychology, CB# 3500 Measurement, and Evaluation University of North Carolina PHONE (919)-962-7848 Chapel Hill, NC 27599-3500 FAX: (919)-962-1533 http://www.unc.edu/~wbware/ EMAIL: [EMAIL PROTECTED] __________________________________________________________________________ On Fri, 5 Oct 2001, Robert J. MacG. Dawson wrote: > > > jeff rasmussen wrote: > > > > Dear statistically-enamored, > > > > There was a question in my undergrad class concerning how to define the > > range, where a student pointed out that contrary to my edict, the range was > > "the difference between the maximum & minimum". I'd always believed that > > the correct answer was the "difference between the maximum & minimum plus > > one" > > One what? Any statistic that depends on the units used seems rather > arbitrary to me. If I compute the range of weights of a group of people > (in kilograms) I ought to get the same actual *weight* as an American > using pounds or a Brit using stones. > > Suppose I have three meter sticks - are you telling us that the range > of their lengths is a little over one meter? > > I'm afraid I vote with your students. > > -Robert Dawson > > > ================================================================= > Instructions for joining and leaving this list and remarks about > the problem of INAPPROPRIATE MESSAGES are available at > http://jse.stat.ncsu.edu/ > ================================================================= > ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================