condition mean min max ZT0-3 4.373835 4.373835 4.373835 ZT4-7 4.0115549999999995 4.0115549999999995 4.0115549999999995 ZT8-11 4.025585 4.025585 4.025585 ZT12-15 5.318965 5.318965 5.318965 ZT16-19 7.701085 7.701085 7.701085 ZT20-23 5.064435 5.064435 5.064435