condition mean min max ZT0-3 493.66193 493.66193 493.66193 ZT4-7 430.65840000000003 430.65840000000003 430.65840000000003 ZT8-11 336.233856 336.233856 336.233856 ZT12-15 317.5350085 317.5350085 317.5350085 ZT16-19 209.5232855 209.5232855 209.5232855 ZT20-23 186.91972099999998 186.91972099999998 186.91972099999998