condition mean min max ZT0-3 8.721264999999999 8.721264999999999 8.721264999999999 ZT4-7 8.25396 8.25396 8.25396 ZT8-11 8.540569999999999 8.540569999999999 8.540569999999999 ZT12-15 6.737385 6.737385 6.737385 ZT16-19 8.156220000000001 8.156220000000001 8.156220000000001 ZT20-23 8.96904 8.96904 8.96904