Appendix B: Sashelp Data Sets

The Sashelp.Burrows data set contains the locations of 2,089 burrows, which are the habitat of isopods ("pill bugs") in the Negev desert in Israel (Banerjee and Gelfand 2002). Each burrow has a Status variable that records whether a burrow still contains live isopods, has been emptied by an isopod predator, or has failed for some other environmental reason. The data set also contains covariates, which are measured on a square-meter grid over the study region. These covariates include topographical characteristics such as Elevation, Slope, Aspect, and PercentRock (the percentage of rocks). The data set also contains environmental characteristics such as PercentShrub (the percentage of shrubs) and Dew (the time in hours since midnight required to evaporate the dew). The following steps display information about the data set Sashelp.Burrows and create Figure 47:

title 'Burrows Data';
proc contents data=sashelp.burrows varnum;
   ods select position;
run;

title 'The First Five Observations Out of 24,591';
proc print data=sashelp.burrows(obs=5);
run;

proc format;
   value bf -1 = "Killed by Predator" 0 = "Failed" 1 = "Successful";
run;

title 'The Status Variable';
proc freq data=sashelp.burrows;
   tables status;
   format status bf.;
run;