condition mean min max ZT0-3 2.4119963970000002 1.918202388 2.9057904060000004 ZT4-7 4.7641525732500005 4.3966797070000005 5.1316254395000005 ZT8-11 8.5993565425 5.759593765 11.43911932 ZT12-15 18.2083921475 17.194172725 19.222611569999998 ZT16-19 19.934394437499996 19.210484684999997 20.65830419 ZT20-23 17.257707105 16.55224349 17.96317072