I'm not so sure about that "proportional test"... On Sun, 10 Nov 2002, Gartland, Myles wrote:
> I am stuck on how to determine if there is a statistical difference > between two time series of aggregate percentages. Two groups (n=~80) > were surveyed each year for 7 years, and their aggregate median cost > percentage was reported. > > >From 1993 to 1999- > > Group A median percentage- 51.91%, 52.73%, ..., 54.17% > Group B median percentage- 60.13%, 57.03%, ..., 67.30% > This is all the information I have other than the sample size for > each year for each group (they are about n=80 per group per year). > I do not have percentages from each individual respondent, just an > aggregate percentage for the group. > > I assume I can call these proportions since they are stated in > percentages. This looks to me like a red herring that has little to do with the question(s) you want to ask. > My hypothesis question is if group B is statistically higher and > increasing at a statistically higher rate then group A. This looks to me like two questions: (1) Is there a difference in overall level between series A and series B? (2) Is there a difference in the rate of change between A and B? > However, I am stuck on how to test. I would have assumed a > chi-square, but my limited background in chi-square (if that is > appropriate) cannot figure out what to do. > > Any ideas? Myles Gartland What do your separate analyses of the two series tell you? ----------------------------------------------------------------------- Donald F. Burrill [EMAIL PROTECTED] 56 Sebbins Pond Drive, Bedford, NH 03110 (603) 626-0816 [was: 184 Nashua Road, Bedford, NH 03110 (603) 471-7128] . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
