condition mean min max ZT0-3 27.771975 22.9424 32.60155 ZT4-7 26.38705 26.38705 26.38705 ZT8-11 20.419849999999997 20.419849999999997 20.419849999999997 ZT12-15 0 0 0 ZT16-19 21.178800000000003 21.178800000000003 21.178800000000003 ZT20-23 17.3772 17.3772 17.3772