condition mean min max ZT0-3 23.447844 23.447844 23.447844 ZT4-7 18.205771 18.205771 18.205771 ZT8-11 18.930773 18.930773 18.930773 ZT12-15 15.614808 15.614808 15.614808 ZT16-19 13.403946000000001 13.403946000000001 13.403946000000001 ZT20-23 11.310568 11.310568 11.310568