FREQUENCY HISTOGRAM: NUMBER OF DIVES 

 DURING A FOUR HOUR SUMMARY PERIOD 

 PTT 843 - 1989 



20 



O 



a:: 



5 - 



- 







120 160 200 240 280 320 



NUMBER OF DIVES 



360 



400 



Figure 39. Frequency histogram of number of dives during a 4-hour summary period for 

 PTT #843 (1989). 



67 



