Dear R users, I came up to a problem by taking means (or other summary
statistics) of a big dataframe.

Suppose we do have a dataframe:

ID  V1  V2  V3  V4 ........................ V71
 1    6     5    3     2  ........................  3
 2    3     2    2     1  ........................  1
 3    6     5    3     2  ........................  3
 4    12   15  3     2  ........................  100
........................................................
........................................................
288 10  20  30   30 .......................... 499

I need to find out the way, how to calculate a mean of every 12 lines to
get:

V1                              V2                V3                 V4
........................... V71
mean from 1 to 7       same as V1    same as V1
mean from 8 to 14     same as V1    same as V1
etc.

I can do it column by column using:

y.ts <- ts(y$V1, frequency=12)
aggregate(y.ts, FUN=mean)

Bu this is a hardcore... Can anyone suggest a better way to compute all the
dataframe at once and get a result as matrix?

Thank you in advance!

-- 
Simonas Kecorius
**

	[[alternative HTML version deleted]]


