condition mean min max ZT0-3 3.2518925092499997 2.592658053 3.9111269654999994 ZT4-7 4.23262103375 3.9194466534999997 4.5457954140000005 ZT8-11 4.148941439750001 3.8887364280000005 4.4091464515 ZT12-15 7.9143790725 6.325190528 9.503567617 ZT16-19 11.23189526225 10.128287089499999 12.335503435 ZT20-23 15.335011245 13.72021052 16.94981197