condition mean min max ZT0-3 2.75 2.75 2.75 ZT4-7 4.0 4.0 4.0 ZT8-11 4.6 4.6 4.6 ZT12-15 5.75 5.75 5.75 ZT16-19 1.5499999999999998 1.5499999999999998 1.5499999999999998 ZT20-23 11.2 11.2 11.2