condition mean min max ZT0-3 15.589458333333333 6.721275 21.22815 ZT4-7 8.985645000000002 8.985645000000002 8.985645000000002 ZT8-11 9.058935 9.058935 9.058935 ZT12-15 13.206925 12.556799999999999 13.857050000000001 ZT16-19 19.756700000000002 19.756700000000002 19.756700000000002 ZT20-23 24.6725 24.6725 24.6725