condition mean min max ZT0-3 2.29581026325 0.300334237 4.2912862894999995 ZT4-7 6.7689441925 5.7336235605 7.804264824500001 ZT8-11 8.231941913 7.483378548999999 8.980505277 ZT12-15 11.663453865000001 11.02565294 12.30125479 ZT16-19 12.0129144675 11.42462157 12.601207365 ZT20-23 10.355965135 9.833375013000001 10.878555256999999