condition mean min max ZT0-3 1.074295 0.4716325 1.4890825 ZT4-7 0.299209 0.299209 0.299209 ZT8-11 1.54866 1.54866 1.54866 ZT12-15 2.0887675000000003 1.756745 2.42079 ZT16-19 1.5501999999999998 1.5501999999999998 1.5501999999999998 ZT20-23 1.093465 1.093465 1.093465