my @prob = (0.1, 0.25, 0.03, 0.4, 0.22);

##</code><code>##

my @options = qw(monday tuesday wednesday thursday friday);

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

my @likelihood = (1,3,4,9);
my @option    = qw(foo bar baz quux);

my @sum;

$sum[0] = $likelihood[0];

foreach my $n ( 1 .. $#likelihood){
    $sum[$n] = $sum[$n - 1] + $likelihood[$n]; 
}

# @sum = (1, 4, 8, 17);

my $n = int(rand($sum[-1])+0.1);  # random number <= 17

foreach my $i ( 0 .. $#sum) {
    if($n <= $sum[$i]){
         print $option[$i] . "\n";;
         last;
      }
}