condition mean min max ZT0-3 4.20977 4.20977 4.20977 ZT4-7 4.791905 4.791905 4.791905 ZT8-11 3.3518999999999997 3.3518999999999997 3.3518999999999997 ZT12-15 4.63668 4.63668 4.63668 ZT16-19 4.04866 4.04866 4.04866 ZT20-23 4.4504150000000005 4.4504150000000005 4.4504150000000005