condition mean min max ZT0-3 7.842601666666667 6.88575 8.971135 ZT4-7 7.734159999999999 7.734159999999999 7.734159999999999 ZT8-11 7.783675 7.783675 7.783675 ZT12-15 7.7891900000000005 7.78331 7.795070000000001 ZT16-19 7.83092 7.83092 7.83092 ZT20-23 10.306090000000001 10.306090000000001 10.306090000000001