condition mean min max ZT0-3 2.2528538333333334 0.4388565 3.39092 ZT4-7 1.0756845 1.0756845 1.0756845 ZT8-11 1.82212 1.82212 1.82212 ZT12-15 4.052842500000001 4.032075 4.07361 ZT16-19 4.02088 4.02088 4.02088 ZT20-23 4.24646 4.24646 4.24646