condition mean min max ZT0-3 18.449825 18.2675 18.632150000000003 ZT4-7 20.06695 20.06695 20.06695 ZT8-11 26.3825 26.3825 26.3825 ZT12-15 0 0 0 ZT16-19 24.4269 24.4269 24.4269 ZT20-23 24.826999999999998 24.826999999999998 24.826999999999998