condition mean min max ZT0-3 4.371926666666666 0.0 8.704835 ZT4-7 2.081625 2.081625 2.081625 ZT8-11 6.331215 6.331215 6.331215 ZT12-15 6.64889 4.677115 8.620664999999999 ZT16-19 5.981665 5.981665 5.981665 ZT20-23 2.30431 2.30431 2.30431