Thank you for your reply.
I've already done that in order to find what the crons files are.
So the cron file which interests me is cron_daily.php. I've watched out this file and I assume the parts to erase in this script are :
// Create webalizer statistics
// Creat awstats statistics
Can you confirm I am right?
Then can I totally uninstall awstats and webalizer or should it be safer to keep them installed as they already are?