```Date: Tue, 5 Feb 2002 13:35:40 -0600 Reply-To: "R.C. Intrieri" Sender: "SPSSX(r) Discussion" From: "R.C. Intrieri" Subject: A statistical Question Content-Type: text/plain; charset="iso-8859-1"; format=flowed Dear Colleagues, This is more of a statistical question rather than strictly an SPSS question. I am attempting to explain the formula to calculate the Median from Grouped data. The formula for this is the following Md = Lm + w [(n/2 – fcum)/fm] Lm = lower limit of the interval that contains the median. W = width of the interval fm = is the frequency fcum = the number of observations falling below this interval. The formula comes from Glass & Hopkins (3rd edition) Statistical methods in education and psychology EQ 4.1 P.52 The question that I have (and I need a reference if possible) is what is the justification from a theoretical point of view for using "the number of observations falling below the interval" as opposed to using the number of observations falling above the interval? Any help would be greatly appreciated. Thanks. Bob Intrieri Robert C. Intrieri, PhD Office (309) 298-1336 Department of Psychology Fax (309) 298-2179 Western Illinois University E-mail RC-Intrieri@wiu.edu 1 University Circle Macomb IL 61455-1390 ```

Back to: Top of message | Previous page | Main SPSSX-L page