condition mean min max ZT0-3 6.9949433333333335 5.41315 8.439985 ZT4-7 6.156845000000001 6.156845000000001 6.156845000000001 ZT8-11 8.12334 8.12334 8.12334 ZT12-15 9.9409725 8.165795000000001 11.716149999999999 ZT16-19 10.096415 10.096415 10.096415 ZT20-23 9.338335 9.338335 9.338335