1000 Observation Sample
from an Exponential Distribution 

 Frequency                                                      
                                                                
 300 +                                                          
     |                                                          
     |                                                          
     |                                                          
     |                                                          
 250 +                                                          
     |                                                          
     |                                                          
     |                                                          
     |                                                          
 200 +                                                          
     |                                                          
     |                                                          
     |                                                          
     |                                                          
 150 +                                                          
     |                                                          
     |                                                          
     |                                                          
     |                                                          
 100 +*                                                         
     |*                                                         
     |*** *                                                     
     |*****                                                     
     |*****  *                                                  
  50 +********                                                  
     |***********                                               
     |************ *                                            
     |*************** **   *                                    
     |************************* *** *** *     *              *  
     ---------------------------------------------------------  
      0    0    1    1    2    2    3    3    4    4    5    5  
      .    .    .    .    .    .    .    .    .    .    .    .  
      0    5    0    5    0    5    0    5    0    5    0    5  
      5    5    5    5    5    5    5    5    5    5    5    5  
                                                                
                             X Midpoint