condition mean min max ZT0-3 6.337125 6.337125 6.337125 ZT4-7 3.9423399999999997 3.9423399999999997 3.9423399999999997 ZT8-11 3.33089 3.33089 3.33089 ZT12-15 5.0285150000000005 5.0285150000000005 5.0285150000000005 ZT16-19 7.0605 7.0605 7.0605 ZT20-23 7.5709599999999995 7.5709599999999995 7.5709599999999995