condition mean min max ZT0-3 4.589898333333333 3.935625 5.565265 ZT4-7 7.521265 7.521265 7.521265 ZT8-11 4.312725 4.312725 4.312725 ZT12-15 7.9872075 3.5143000000000004 12.460115 ZT16-19 5.194425 5.194425 5.194425 ZT20-23 4.88492 4.88492 4.88492