condition mean min max ZT0-3 11.361605 10.13421 12.589 ZT4-7 6.4810300000000005 6.4810300000000005 6.4810300000000005 ZT8-11 5.911795 5.911795 5.911795 ZT12-15 0 0 0 ZT16-19 9.255965 9.255965 9.255965 ZT20-23 9.722674999999999 9.722674999999999 9.722674999999999