Some Perl help needed

[Aquous]

Hello,

For a homework assignment (statistics, yay...) I need to generate two sets of data. Both data sets need to consist of 30 fictional test subjects, who underwent different treatments. One treatment yields a mean score of 6 on some scale, the second treatment yields a mean score of 7. As a frustrating extra bonus my teacher wants the within-groups variation to be realistic, so I can't just give every test subject a 6 or a 7.
Once I've generated those two fictional data sets I need to do some nasty stuff to them using SPSS which I won't bother you with

So I thought: let's solve this first part of the problem using the computer. If I have 30 subjects, the first 29's scores can practically be any value, but the last subject needs to score a specific number to make the means add up to 6 or 7. I have successfully written a Perl program that can generate this fictional data for one group of test subjects.
However, I need to generate the data for two groups. I will also need the data to be in a 3x30 matrix. In other words: I need to generate the fictitious data, store it into an array result by result, do this again to yield two arrays containing different results, then printing the first line of each array, then the second, et cetera.

I can't get that to work.

The code is uploaded here: http://pastebin.com/GXKM81Ae

So, a quick walkthrough of what I'm trying to do in the program, because it is a bit dense and I didn't comment it (bad practice, I know):
The program expects to be given as command-line arguments the number of participants (30 in this case) and all means it should come up with (6 and 7 in this case). It then creates an empty array @pointers. This array will contain pointers/references to the arrays containing the results, which are calculated in the subroutine 'calculate'. After that (starting at line 13) it starts a counter at 0, prints the value of this counter with 1 added to it (the participant's number) followed by a tab and the $i-th element of each array whose memory location is stored in the array @pointers. (Complicated, I know.)

The problem: all generated arrays of scores are identical.
e.g. if you run the program as "./program 5 1 2 3 4" it should yield 4 arrays, having a mean of 1, 2, 3, and 4, containing 5 scores in total which deviate from the expected mean of 1/2/3/4 by no more than 2 scores and which add up to (5*1/2/3/4). That doesn't happen however: I get one array of scores which is duplicated four times.

Can anyone spot the (probably very obvious) mistake?

[BitJam]