condition mean min max ZT0-3 3.3897749999999998 3.3654599999999997 3.41409 ZT4-7 2.437715 2.437715 2.437715 ZT8-11 2.654845 2.654845 2.654845 ZT12-15 0 0 0 ZT16-19 4.316015 4.316015 4.316015 ZT20-23 3.234935 3.234935 3.234935