condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 8.62655 8.62655 8.62655 ZT8-11 8.366254999999999 8.366254999999999 8.366254999999999 ZT12-15 7.6556345 7.6556345 7.6556345 ZT16-19 8.9507165 8.9507165 8.9507165 ZT20-23 7.842095 7.842095 7.842095