condition mean min max ZT0-3 2.204575 2.204575 2.204575 ZT4-7 1.55253 1.55253 1.55253 ZT8-11 1.0621200000000002 1.0621200000000002 1.0621200000000002 ZT12-15 2.50665 2.50665 2.50665 ZT16-19 2.183095 2.183095 2.183095 ZT20-23 1.6952150000000001 1.6952150000000001 1.6952150000000001