condition mean min max ZT0-3 16.518537 16.518537 16.518537 ZT4-7 15.398323999999999 15.398323999999999 15.398323999999999 ZT8-11 12.900692 12.900692 12.900692 ZT12-15 12.4093655 12.4093655 12.4093655 ZT16-19 12.819842000000001 12.819842000000001 12.819842000000001 ZT20-23 14.9404285 14.9404285 14.9404285