condition mean min max ZT0-3 1.887035 1.887035 1.887035 ZT4-7 1.5289350000000002 1.5289350000000002 1.5289350000000002 ZT8-11 2.252575 2.252575 2.252575 ZT12-15 2.13065 2.13065 2.13065 ZT16-19 2.03328 2.03328 2.03328 ZT20-23 1.836435 1.836435 1.836435