 Usage:  plotboxgrouped (ug, og, n {, col})  
 
 Input:

  ug                     p x 1 sorted vector of lower borders of group 
                         
  og                     p x 1 sorted vector of upper borders of group 
                         
  n                      p x 1 vector of absolute or relative frequencies of group 
                         
  col                    color 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
