/*------------------------------------------------------------*/
/*                                                            */
/*SAS Example VII      Stat345       Categorical Data Analysis*/
/*                                                            */
/*Socioeconomic Status / Smoking Study                        */
/*                                                            */
/*------------------------------------------------------------*/

Options LS=78;

Data Smoke;
  INPUT Soc_Econ Smoker $ Age $ Freq;
  Cards;
  1   S  <55  84
  1   S  55+  22
  1  NS  <55  87
  1  Ns  55+ 135
  2   S  <55  44
  2   S  55+  12
  2  NS  <55  41
  2  NS  55+  44
  3   S  <55  26
  3   S  55+  17
  3  NS  <55  22
  3  NS  55+  57
  4   S  <55  17
  4   S  55+  14
  4  NS  <55  19
  4  NS  55+  21
  ;

/*Analyze the data using Proc FREQ.                           */
/*  The 'Order=Data' specification maintains the ordering of  */
/*     the variable levels in which the data was input.       */
/*  The 'Weight' statement identifies the cell frequency      */
/*     variable.                                              */
/*  The 'By' statement produces a separate analysis for each  */
/*     level of the designated variable. The data set must be */
/*     previously sorted by this variable using Proc SORT.    */
/*  The 'ChiSq' option produces results for chi-squared tests */
/*     of independence (e.g., Pearson chi-squared, likelihood */
/*     ratio).                                                */
/*  The 'Trend' option produces the Cochran-Armitage linear   */
/*     trend test.                                            */
/*  The 'Title' statement assigns a heading to each page of   */
/*     output.                                                */

Proc SORT;
  By Age;

Proc FREQ Order = Data;
  Weight Freq;
  By Age;
  Tables Soc_Econ*Smoker / ChiSq Trend;
  Title 'Socioeconomic Status / Smoking Study (1977)';
  Title '(Status Indides from 1 [Low] to 5 [High])';
  Title '(Separate Analyses by Age)';
  Run;