condition mean min max ZT0-3 13.213158 13.213158 13.213158 ZT4-7 11.8488365 11.8488365 11.8488365 ZT8-11 12.390806000000001 12.390806000000001 12.390806000000001 ZT12-15 13.156257 13.156257 13.156257 ZT16-19 14.6030505 14.6030505 14.6030505 ZT20-23 16.502858500000002 16.502858500000002 16.502858500000002