condition mean min max ZT0-3 3.6915199999999997 3.2639 4.030295 ZT4-7 1.8447455000000001 1.8447455000000001 1.8447455000000001 ZT8-11 2.433415 2.433415 2.433415 ZT12-15 6.0399575 5.55039 6.529525 ZT16-19 4.7199349999999995 4.7199349999999995 4.7199349999999995 ZT20-23 6.379315 6.379315 6.379315