condition mean min max ZT0-3 5.25 5.25 5.25 ZT4-7 8.5 8.5 8.5 ZT8-11 6.7 6.7 6.7 ZT12-15 6.6499999999999995 6.6499999999999995 6.6499999999999995 ZT16-19 4.75 4.75 4.75 ZT20-23 5.0 5.0 5.0