summary(x1); sd(x1)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  33.58   43.73   47.31   48.90   53.30   67.84
[1] 7.030837   # StDev

summary(x2); sd(x2)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  34.53   44.73   48.27   49.91   54.36   68.82
[1] 7.028975   # StDev

cor(x1, x2)
[1] 0.9998922  # Sample correlation