condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 9.532974 9.532974 9.532974 ZT8-11 8.5822515 8.5822515 8.5822515 ZT12-15 10.004810500000001 10.004810500000001 10.004810500000001 ZT16-19 8.272221 8.272221 8.272221 ZT20-23 8.923299 8.923299 8.923299