condition mean min max ZT0-3 4.273045 4.273045 4.273045 ZT4-7 2.70397 2.70397 2.70397 ZT8-11 4.249085 4.249085 4.249085 ZT12-15 6.21325 6.21325 6.21325 ZT16-19 6.92399 6.92399 6.92399 ZT20-23 4.302475 4.302475 4.302475