Based on the data presented in Figure 
,
I can suggest several conclusions about the evolution of
young stars. The results of the Kolmogorov--Smirnov (KS) tests with
the data presented here and those of Choi & Herbst (1996) on
similar regions of the histogram indicate that
there is something which holds stars near eight day periods.
Stars in different regions also seem to share a similar mechanism
which regulates the fast rotators. Further, it seems that stars migrate
from the slow rotating (SR) group to the fast rotating (FR) group
as a function of time. To gain the most information out of the
data presented here one can combine these data with those
of other authors. Before that can be done, one should first discuss
the biases in the data sets.