condition mean min max ZT0-3 30.129695 30.129695 30.129695 ZT4-7 34.477363 34.477363 34.477363 ZT8-11 35.963266 35.963266 35.963266 ZT12-15 37.68172 37.68172 37.68172 ZT16-19 34.519000500000004 34.519000500000004 34.519000500000004 ZT20-23 31.1485865 31.1485865 31.1485865