IRIS-HISTOGRAM
              ┌                                        ┐ 
   [4.0, 4.5) ┤▇▇▇▇▇ 4                                   
   [4.5, 5.0) ┤▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 18                   
   [5.0, 5.5) ┤▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 30     
   [5.5, 6.0) ┤▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 31    
   [6.0, 6.5) ┤▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 32   
   [6.5, 7.0) ┤▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇ 22              
   [7.0, 7.5) ┤▇▇▇▇▇▇▇▇ 7                                
   [7.5, 8.0) ┤▇▇▇▇▇▇▇ 6                                 
              └                                        ┘ 
                              Frequency