x => r2017.11.06-update-zipfian-throughput.log 
y => 9acbd68815499fc7f8fbb5931d643b8fd7804a80-update-zipfian-throughput.log 

     n min   max median  average   stddev      p99
x 3600   0 21598  19391 16941.29 6036.165 21204.16
y 3600   0 21779  19490 16915.36 6152.234 21232.01

6000        17000       18000        19000       20000       21000        22000 
 |------------+-----------+------------+-----------+-----------+------------+--|
                                +-----------+------+                            
1    ---------------------------|           |      |--------------------        
                                +-----------+------+                            
                                 +-----------+-----+                            
2     ---------------------------|           |     |----------------------      
                                 +-----------+-----+                            
Legend: 1=data$x, 2=data$y

At 95% probablitiy:
===> average not statistically significant    (p=0.856801, diff ~25.921944)
===> variance not statistically significant   (p=0.253243)