condition mean min max ZT0-3 2.53764465675 1.816115084 3.2591742294999997 ZT4-7 4.4540858935 3.7661472105 5.1420245765 ZT8-11 6.9916799855 5.9879572415 7.9954027295 ZT12-15 8.874225372249999 8.208542298 9.5399084465 ZT16-19 15.39854598 13.70455208 17.09253988 ZT20-23 19.764584745 18.958333855 20.570835635