condition mean min max ZT0-3 4.422835 3.605795 5.239875 ZT4-7 4.6336949999999995 4.6336949999999995 4.6336949999999995 ZT8-11 4.58446 4.58446 4.58446 ZT12-15 0 0 0 ZT16-19 5.693125 5.693125 5.693125 ZT20-23 5.206025 5.206025 5.206025