condition mean min max ZT0-3 6.5375325 5.75839 7.316675 ZT4-7 6.549685 6.549685 6.549685 ZT8-11 5.45472 5.45472 5.45472 ZT12-15 0 0 0 ZT16-19 6.947855000000001 6.947855000000001 6.947855000000001 ZT20-23 6.66158 6.66158 6.66158