Hi, Dennis. You did not address the question, so far as I can see. You stated an answer, which I take to be your personal opinion on the point, but you supplied no supporting arguments. I had asked "are those properly called 'z' scores?", because z scores are commonly defined in terms of population values (aka parameters), while the values I was questioning were calculated from sample values. Possibly a minor and not-very-interesting point, but I'm unwilling to take an unsupported assertion as a reasoned reply ;-).
I guess I don't see the quibble point. By definition ... a z score ... which has mean = 0 and sd = 1 ... is a scale that tells how many sd units a score is from the mean
Now, if you had population data ... then the z would refer to THE position of a score around the mu value ... however, if you have sample data and are interested in what the z MIGHT be in that population for the given X value ... then I would assume that the z is an estimate of what THAT score would have as a z ...
I picked up 3 random books on my shelf and they said:
Ferguson (old book) ... A standard score is a deviation from the mean divided by the standard deviation .... (note: z is just one example of that)
Glass and Stanley ... show z = (X - X BAR) / S(x) ... and we know that their terminology is to use S as an estimate of sigma
Moore and McCabe ... in their section on a ND( with mu and sigma) say that if you subtract mu from X and divide by sigma ... this is "often" called a z score ... I see nothing in their discussion (there or later) that restricts z to a population case ... having mu and sigma
I have never seen such a distinction that you are suggesting ... doesn't mean you are incorrect but ... books seem NOT to distinguish ...
Do you have any explicit example from a text ... that DOES make this distinction?
On Sun, 3 Aug 2003, Dennis Roberts wrote in part:
> At 02:27 AM 8/3/03 -0400, Donald Burrill wrote: > > > >Interesting semantic question, though: Are those properly called "z" > >scores? > > yes they are
----------------------------------------------------------------------- Donald F. Burrill [EMAIL PROTECTED] 56 Sebbins Pond Drive, Bedford, NH 03110 (603) 626-0816
---------------------------------------------------------- Dennis Roberts Email: [EMAIL PROTECTED] Web: http://roberts.ed.psu.edu/users/droberts/drober~1.htm
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