condition mean min max ZT0-3 2.13644 2.13644 2.13644 ZT4-7 2.56929 2.56929 2.56929 ZT8-11 2.786275 2.786275 2.786275 ZT12-15 2.885225 2.885225 2.885225 ZT16-19 3.94456 3.94456 3.94456 ZT20-23 3.01831 3.01831 3.01831