condition mean min max ZT0-3 4.855001666666666 4.06472 5.63425 ZT4-7 4.598145 4.598145 4.598145 ZT8-11 4.29125 4.29125 4.29125 ZT12-15 5.266887499999999 4.662974999999999 5.870799999999999 ZT16-19 6.628495 6.628495 6.628495 ZT20-23 6.13355 6.13355 6.13355