[R] queue waiting times comparison

[Petr PIKAL]

Hallo all

I try to find a way how to compare set of waiting times during different 
periods. I tried learn something from queueing theory and used also R 
search. There is plenty of ways but I need to find the easiest and quite 
simple.
Here is a list with actual waiting times.

ml <- structure(list(y1 = c(10, 9, 9, 10, 8, 20, 16, 47, 4, 7, 15, 
18, 36, 5, 24, 15, 40, 10), y2 = c(97, 10, 26, 11, 11, 10, 5, 
13, 19, 5, 5, 59, 4, 16, 10)), .Names = c("y1", "y2"))

par(mfrow=c(1,2))
lapply(ml, hist)

shows that in the first year is more longer waiting times

lapply(ml, mean)

shows (incorrectly) that in the second year there is longer average 
waiting time.

lapply(ml, mean)

gives me completely reversed values.

Can you please give me some hints what to use for "correct" and "simple" 
comparison of  waiting times in two or more periods.

Thank you
Petr