condition mean min max ZT0-3 1.934015 1.6201400000000001 2.253905 ZT4-7 1.51849 1.51849 1.51849 ZT8-11 2.471795 2.471795 2.471795 ZT12-15 5.6316025 4.859625 6.40358 ZT16-19 4.492825 4.492825 4.492825 ZT20-23 4.2014249999999995 4.2014249999999995 4.2014249999999995