condition mean min max ZT0-3 3.3604849999999997 3.28662 3.43435 ZT4-7 5.67373 5.67373 5.67373 ZT8-11 7.27949 7.27949 7.27949 ZT12-15 0 0 0 ZT16-19 7.57799 7.57799 7.57799 ZT20-23 6.171665 6.171665 6.171665