condition mean min max ZT0-3 2.612665 2.612665 2.612665 ZT4-7 1.413657 1.413657 1.413657 ZT8-11 0.7210920000000001 0.7210920000000001 0.7210920000000001 ZT12-15 3.014315 3.014315 3.014315 ZT16-19 5.008205 5.008205 5.008205 ZT20-23 3.3423 3.3423 3.3423