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From | Nick Cox <n.j.cox@durham.ac.uk> |
To | "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu> |
Subject | st: RE: differences in percentages across categories |
Date | Fri, 20 Jan 2012 13:27:20 +0000 |
And Comparing Two Proportions from the Same Survey C. J. Wild and G. A. F. Seber The American Statistician , Vol. 47, No. 3 (Aug., 1993), pp. 178-181 Nick n.j.cox@durham.ac.uk -----Original Message----- From: Nick Cox Sent: 20 January 2012 13:25 To: 'statalist@hsphsun2.harvard.edu' Subject: RE: differences in percentages across categories This sounds like Difference of Proportions from the Same Survey Alastair J. Scott and George A. F. Seber The American Statistician , Vol. 37, No. 4, Part 1 (Nov., 1983), pp. 319-320 I am not aware of a canned implementation in Stata. Nick n.j.cox@durham.ac.uk -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Mirko Moro Sent: 20 January 2012 10:47 To: statalist@hsphsun2.harvard.edu Subject: st: differences in percentages across categories Dear Statlisters, Imagine I have 2 categorical variables, say Repair Record in 1978 and Headroom (suppose I treat Headroom as categorical variable): . sysuse auto (1978 Automobile Data) . tab rep78 headroom, row nofreq Repair | Record | Headroom (in.) 1978 | 1.5 2.0 2.5 3.0 3.5 4.0 | Total -----------+------------------------------------------------------------------+---------- 1 | 50.00 50.00 0.00 0.00 0.00 0.00 | 100.00 2 | 0.00 37.50 0.00 0.00 12.50 25.00 | 100.00 3 | 0.00 16.67 16.67 13.33 33.33 10.00 | 100.00 4 | 11.11 5.56 27.78 16.67 11.11 27.78 | 100.00 5 | 0.00 27.27 36.36 36.36 0.00 0.00 | 100.00 -----------+------------------------------------------------------------------+---------- Total | 4.35 18.84 20.29 15.94 18.84 14.49 | 100.00 Repair | Record | Headroom (in.) 1978 | 4.5 5.0 | Total -----------+----------------------+---------- 1 | 0.00 0.00 | 100.00 2 | 12.50 12.50 | 100.00 3 | 10.00 0.00 | 100.00 4 | 0.00 0.00 | 100.00 5 | 0.00 0.00 | 100.00 -----------+----------------------+---------- Total | 5.80 1.45 | 100.00 I would like to test whether the percentage of car with headroom equal to 1.5 inch vary across repair records, after that I wish to know whether the percentage of car with headroom equal to 2.5 inch vary across repair records, and so on. Is there a way to do this or I need multinomial models with varying baseline and reference categories? * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/