condition mean min max ZT0-3 7.341923333333333 5.880800000000001 8.137595 ZT4-7 5.7986450000000005 5.7986450000000005 5.7986450000000005 ZT8-11 6.530575000000001 6.530575000000001 6.530575000000001 ZT12-15 5.8794425 4.64286 7.1160250000000005 ZT16-19 5.076055 5.076055 5.076055 ZT20-23 7.393395 7.393395 7.393395