N    Y    sample_mean sample_stddev
   1  482     482.000       0.000
   2  521     501.500      27.577
   3  494     499.000      19.975
   4  512     502.250      17.557
   5  485     498.800      17.050
   6  507     500.167      15.613

 395  493     500.258      16.163
 396  505     500.270      16.144
 397  501     500.272      16.124
 398  494     500.256      16.107
 399  501     500.258      16.086
 400  474     500.192      16.120

N    Y    sample_mean sample_stddev
   1  616     616.000       0.000
   2  584     600.000      22.627
   3  620     606.667      19.732
   4  617     609.250      16.919
   5  583     604.000      18.775
   6  613     605.500      17.190

 395  608     599.484      17.031
 396  615     599.523      17.027
 397  609     599.547      17.013
 398  607     599.565      16.995
 399  604     599.576      16.975
 400  611     599.605      16.964