Ciao,
M.

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Note added at 2002-05-21 15:41:48 (GMT)
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\"The Bross test (RIDIT
analysis) has been applied to compare among groups
the intensity of adverse events according to the scale:
severe, moderate and slight.\"
\"El test de Bross (análisis
RIDIT) se ha aplicado para comparar entre grupos la
intensidad de los acontecimientos adversos según la
escala: severo, moderada y leve.
adverse events.\"
http://216.239.39.100/search?q=cache:PltBuOJ-MGgC:www.pharma...

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The FREQ Procedure



Definitions and Notation
In this chapter, a two-way table represents the crosstabulation of variables X and Y. Let the rows of the table be labeled by the values Xi, i = 1, 2, ... , R, and the columns by Yj, j = 1, 2, ... , C. Let nij denote the cell frequency in the ith row and the jth column and define the following:



Scores
PROC FREQ uses scores for the variable values when computing the Mantel-Haenszel chi-square, Pearson correlation, Cochran-Armitage test for trend, weighted kappa coefficient, and Cochran-Mantel-Haenszel statistics. The SCORES= option in the TABLES statement specifies the score type that PROC FREQ uses. The available score types are TABLE, RANK, RIDIT, and MODRIDIT scores. The default score type is TABLE.
For numeric variables, table scores are the values of the row and column levels. If the row or column variables are formatted, then the table score is the internal numeric value corresponding to that level. If two or more numeric values are classified into the same formatted level, then the internal numeric value for that level is the smallest of these values. For character variables, table scores are defined as the row numbers and column numbers (that is, 1 for the first row, 2 for the second row, and so on).

Rank scores, which you can use to obtain nonparametric analyses, are defined by


Note that rank scores yield midranks for tied values.
Ridit scores (Bross 1958; Mack and Skillings 1980) also yield nonparametric analyses, but they are standardized by the sample size. Ridit scores are derived from rank scores as


Modified ridit (MODRIDIT) scores (van Elteren 1960; Lehmann 1975), which also yield nonparametric analyses, represent the expected values of the order statistics for the uniform distribution on (0,1). Modified ridit scores are derived from rank scores as



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Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.

Otra opción totalmente en español.

Saludos. :o)

http://bvs.sld.cu/revistas/hih/vol13_2_97/hih07297.htm

Se investigó la deficiencia de sustancia precursora H de los grupos sanguíneos A y AB, en 547 donantes de sangre (397 blancos y 150 negros). Se estimó el rango de puntuación de la aglutinación de un grupo control de 40 donantes, correspondientes a los grupos sanguíneos A1, A2, A1B y A2B. En el suero de los donantes deficientes de H se determinó la presencia de anticuerpos eritrocitarios. En los donantes blancos el grupo A1 predominó sobre el A2, de forma contraria ocurrió en los negros. En los 2 grupos raciales estudiados, tanto para el grupo A como el AB, se encontraron variantes deficientes de H codificadas por los genes A1 y A2. En toda la muestra se halló una mayor frecuencia de variantes deficientes A2B, especialmente en los negros. No se observaron anticuerpos anti-H en el suero de las variantes.