condition mean min max ZT0-3 5.738685 5.738685 5.738685 ZT4-7 6.9153649999999995 6.9153649999999995 6.9153649999999995 ZT8-11 3.108835 3.108835 3.108835 ZT12-15 1.93667 1.93667 1.93667 ZT16-19 3.2498400000000003 3.2498400000000003 3.2498400000000003 ZT20-23 6.67836 6.67836 6.67836