condition mean min max ZT0-3 31.751475 25.2364 38.26655 ZT4-7 19.43855 19.43855 19.43855 ZT8-11 21.214085 21.214085 21.214085 ZT12-15 0 0 0 ZT16-19 59.181700000000006 59.181700000000006 59.181700000000006 ZT20-23 46.060649999999995 46.060649999999995 46.060649999999995