condition mean min max ZT0-3 8.87164 7.6891549999999995 10.054124999999999 ZT4-7 14.7834 14.7834 14.7834 ZT8-11 29.33455 29.33455 29.33455 ZT12-15 0 0 0 ZT16-19 26.518 26.518 26.518 ZT20-23 16.95315 16.95315 16.95315