/* Lab 5 */

/* Exploratory Analysis */
filename nc url 'http://www.openintro.org/stat/data/nc_sas.csv';
 
proc import
  datafile=nc
  out=nc
  dbms=csv
  replace; 
  getnames=yes;
  guessingrows=max;
run;

proc means maxdec=2 data=nc;
   var fage mage weeks visits weight gained;
run;

proc freq data=nc;
   tables mature premie marital lowbirthweight gender habit whitemom;
run;

proc sgplot data=nc;
	vbox weight / category=habit;
run;

proc means data=nc mean maxdec=2;
   class habit;
   var weight;
run;

/* Inference */

proc ttest data=nc sides=2 H0=0;
    class habit;
    var weight;
    title "Two-Sample t-test Comparing Birthweights by Smoking Status";
run;