Peto's Mortality and Prevalence Test with PROC MULTTEST

This script creates a dataset simulating animal observations (tumor types, dose, time of death). It derives a stratification variable (B) based on the time of death (T). Then, the MULTTEST procedure is used to perform a one-sided (uppertailed) Peto test with 20 permutations, stratifying by B and analyzing the effect of dose through a linear contrast.

Data Analysis

Type : CREATION_INTERNE

Data is defined directly in the script via DATALINES (table 'a') and uses the continuous reading format ( @code_sas_json/8_SAS_Intro_ReadFile_MultiCol_@@.json).

1 Code Block

DATA STEP Data

Explanation :
Creation of table 'a' from internal data. The INPUT statement uses ' @@' to read multiple observations on the same physical line. A stratification variable 'B' is conditionally calculated based on the value of 'T'.

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1	DATA a;
2	INPUT S1-S3 T Dose @code_sas_json/8_SAS_Intro_ReadFile_MultiCol_@@.json;
3	IF T<=90 THEN B=1; ELSE B=2;
4	DATALINES;
5	0 0 0 104 0 2 0 1 80 0 0 0 1 104 0
6	0 0 0 104 0 0 2 0 100 0 1 0 0 104 0
7	2 0 0 85 1 2 1 0 60 1 0 1 0 89 1
8	2 0 1 96 1 0 0 0 96 1 2 0 1 99 1
9	2 1 1 60 2 2 0 0 50 2 2 0 1 80 2
10	0 0 2 98 2 0 0 1 99 2 2 1 1 50 2
11	;

2 Code Block

PROC MULTTEST Data

Explanation :
Execution of the MULTTEST procedure to calculate adjusted probabilities. The 'peto' test is specified for variables S1 to S3, taking into account time T and using permutations. The 'out=p' option saves the results.

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1	PROC MULTTEST DATA=a notables out=p stepsid;
2	test peto(S1-S3 / permutation=20 time=T uppertailed);
3	class Dose;
4	strata B;
5	contrast 'mort-prev' 0 1 2;
6	RUN;

3 Code Block

PROC PRINT

Explanation :
Display of the contents of output table 'p' containing statistical results (p-values).

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1	PROC PRINT DATA=p;
2	RUN;

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