condition mean min max ZT0-3 3.452636666666667 3.047395 3.99676 ZT4-7 3.402005 3.402005 3.402005 ZT8-11 5.420445 5.420445 5.420445 ZT12-15 7.5036725 5.711405 9.29594 ZT16-19 6.728294999999999 6.728294999999999 6.728294999999999 ZT20-23 8.248365 8.248365 8.248365