Killing insects
===============
Data: insecticides.dat 
Keywords: Logistic regression. 
Description: In a trial of three insecticides, batches of about fifty insects
             were exposed to varying deposits of each insecticide. 
Number of observations: 882 
Variable      Description  
killed        Binary variable: killed=1, not-killed=0  
insecticide   Categorical variable identifying insecticide (numbered 1 to 3)  
deposit       Amount of deposit (in milligrams)  

Source: Krzanowski, W.J. (1998) An Introduction to Statistical Modelling, 
        London: Arnold. pp. 198-9.