Choose any distance to the flag from 50-130 yards and get 9 golf balls.
Hit the 9 balls at the flag, going through your full pre-shot routine each time and ensuring you are hitting each ball as close as you possibly can.
When you have hit all 9 balls, go to the green and measure the distance to the flag from each ball in FEET.
Add the distance of each ball together and divide by 9 to find the average distance from the flag.
If this number is more than 10% of the YARDAGE of the shot you were playing, start again and keep going until you achieve this (use 15/20% if 10% is too hard).
Move on when the average distance in FEET is less than 10% of the distance of the shot in YARDs.
This test is designed to be frustrating, test patience and ability to perform under pressure.