condition mean min max ZT0-3 9.341439 9.341439 9.341439 ZT4-7 8.8808615 8.8808615 8.8808615 ZT8-11 9.131212999999999 9.131212999999999 9.131212999999999 ZT12-15 10.0443535 10.0443535 10.0443535 ZT16-19 10.1548575 10.1548575 10.1548575 ZT20-23 10.157778 10.157778 10.157778