Tips & Tricks

From your fellow SAS users

9/30/2004

Mehmet KocakSt. JudeTopic: Shapiro-Wilk Normality Test

Shapiro-Wilk Normality Test

Once you call the macro, here are the parameters you specify: %histogram(data, var,  barnum, byvar=none, group=none, numeric=no, title=); DATA: Data set where you have the variable to check normality; VAR: Variable for which to check normality; BARNUM:Number of bars to be shown in the histogram; BYVAR:  specifies if you want to check normality for some subgroups; GROUP: specifies group for which to check normality; NUMERIC: specifies if the grouping variable is numberic or categorical (numeric=no/yes) ; TITLE: If no title is specified, then the title is "The Histogram of Variable &VAR"; using this TITLE statement, you can add to the default title;

An example can be %histogram(IQData, IQ,  12, byvar=GENDER, group=MALE, numeric=no, title= For Male Patients);

%macro histogram(data, var, barnum, byvar=none, group=none, numeric=no, title=);%if &byvar=none %then %do;proc sql noprint; title ""; select distinct min(&var), max(&var), (max(&var)-min(&var))/&barnuminto :minval, :maxval, :wdt from &data; quit;proc univariate data=&data normal noprint;title "Univariate Analysis for &var";var &var; output out=Normal&data normal=normtest probn=pvalue noprint; run;data _null_; set normal&data; if pvalue<0.001 then do; x="<0.001";call symput("Pvalue", x); end;else call symput ("pvalue", pvalue); run;%let pvalue=%substr(&pvalue, 1,6);proc univariate data=&data normal noprint;title "";var &var; title "Univariate Analysis for &var";title1 height=5 font="complex" bold "Histogram of Variable %upcase(&var) &title";title2 height=5 font=simplex "P-value for Shapiro-Wilk Normality Test=&pvalue";histogram &var/normal(noprint) height=5 font=complex midpoints=&minval to &maxval by &wdt;run;%end;%else %if &byvar^=none and &numeric=no %then %do;proc sql noprint; title ""; select distinct min(&var), max(&var), (max(&var)-min(&var))/&barnuminto :minval, :maxval, :wdt from &data where &byvar="&group"; quit;proc univariate data=&data normal noprint; where &byvar="&group";title height=0.1 "Univariate Analysis for &var in Group %upcase(&group)";var &var; output out=Normal&data normal=normtest probn=pvalue; run;data _null_; set normal&data; if pvalue<0.001 then do; x="<0.001";call symput("Pvalue", x); end;else call symput ("Pvalue", pvalue); run;%let pvalue=%substr(&pvalue, 1,6);proc univariate data=&data noprint; where &byvar="&group";title "";var &var; title "Univariate Analysis for &var in Group %upcase(&group)";title1 height=5 font="complex" bold "Histogram of Variable %upcase(&var) for %upcase(&group) &title";title2 height=5 font=simplex "P-value for Shapiro-Wilk Normality Test=&pvalue";histogram &var/normal(noprint) height=5 font=complex midpoints=&minval to &maxval by &wdt;run;%end;

%else %if &byvar^=none and &numeric^=no %then %do;proc sql noprint; title ""; select distinct min(&var), max(&var), (max(&var)-min(&var))/&barnuminto :minval, :maxval, :wdt from &data where &byvar=&group; quit;proc univariate data=&data normal noprint; where &byvar=&group;title height=0.1 "Univariate Analysis for &var in Group %upcase(&group)";var &var; output out=Normal&data normal=normtest probn=pvalue; run;data _null_; set normal&data; if pvalue<0.001 then do; x="<0.001";call symput("Pvalue", x); end;else call symput ("Pvalue", pvalue); run;%let pvalue=%substr(&pvalue, 1,6);proc univariate data=&data noprint; where &byvar=&group;title "";var &var; title "Univariate Analysis for &var in Group &group";title1 height=5 font="complex" bold "Histogram of Variable %upcase(&var) for &group &title";title2 height=5 font=simplex "P-value for Shapiro-Wilk Normality Test=&pvalue";histogram &var/normal(noprint) height=5 font=complex midpoints=&minval to &maxval by &wdt;run;%end;%mend histogram;

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