condition mean min max ZT0-3 8.677768333333333 1.991205 12.8936 ZT4-7 2.243965 2.243965 2.243965 ZT8-11 2.942895 2.942895 2.942895 ZT12-15 4.6219125000000005 4.154780000000001 5.0890450000000005 ZT16-19 6.477195 6.477195 6.477195 ZT20-23 13.65575 13.65575 13.65575