condition mean min max ZT0-3 3.88925 3.88925 3.88925 ZT4-7 3.260915 3.260915 3.260915 ZT8-11 2.8668 2.8668 2.8668 ZT12-15 2.659315 2.659315 2.659315 ZT16-19 4.41021 4.41021 4.41021 ZT20-23 4.02612 4.02612 4.02612