How can I format the output of ping in bash?
Use

ping -q -n -s $SIZE -c $COUNT $myHost |
    awk -v host=$myhost '/packet loss/ {print host, $7}'


inside the loop. 

In case you only want to print the hosts with packet loss use

ping -q -n -s $SIZE -c $COUNT $myHost |
    awk -v host=$myhost '/packet loss/ {if ($7 != "0.0%") print host, $7}'


Side note: grep pattern | awk '{action}' can usually be replaced with the much neater  (and slightly faster) awk '/pattern/ {action}'