condition mean min max ZT0-3 7.458454328 6.93849096 7.978417695999999 ZT4-7 3.95090574075 3.107769406 4.7940420755 ZT8-11 7.6388984645 6.070692531500001 9.2071043975 ZT12-15 8.59773148 8.5044682955 8.6909946645 ZT16-19 10.79004369575 10.394868438 11.185218953500002 ZT20-23 13.93804589 11.78016473 16.09592705