Random positive decimal number in bash

I would like to make a random ICMP traffic using ping. I need to make a random decimal number between 0.5 to 1 for time parameter in my code. Could you please show me how to make random decimal number? My code just can make a integer number. Thanks

#!/bin/bash

for ((i = 0; i <=100; i++))
do
#need to have random number between 0.5 to 1 for time
time=$(($RANDOM%5+1))
num=$(($RANDOM%5+1)) 

ping -c $time -i $num 10.0.0.2 

done