That seq is probably supposed to be $(seq 0.05 0.05 0.5). Right now it's always 0.05.

Note that you can get random numbers straight from bash with $RANDOM. It's 15 bit (0 to 32767) but good enough here; this would get between 0.05 and 0.5: $(printf "0.%.4d\n" $((500 + RANDOM % 4501)))