condition mean min max ZT0-3 13.149226666666666 4.61908 17.41575 ZT4-7 4.121345 4.121345 4.121345 ZT8-11 5.6964749999999995 5.6964749999999995 5.6964749999999995 ZT12-15 4.8781725 4.77079 4.985555 ZT16-19 7.728445 7.728445 7.728445 ZT20-23 16.9177 16.9177 16.9177