condition mean min max ZT0-3 26.267075 24.91715 27.617 ZT4-7 8.981020000000001 8.981020000000001 8.981020000000001 ZT8-11 7.47193 7.47193 7.47193 ZT12-15 0 0 0 ZT16-19 21.81565 21.81565 21.81565 ZT20-23 35.3166 35.3166 35.3166