condition mean min max ZT0-3 4.594731666666667 1.615645 6.980180000000001 ZT4-7 1.724915 1.724915 1.724915 ZT8-11 3.331385 3.331385 3.331385 ZT12-15 5.4035375000000005 4.37151 6.435565 ZT16-19 7.65617 7.65617 7.65617 ZT20-23 8.443945 8.443945 8.443945