condition mean min max ZT0-3 11.616015 10.092945 12.6994 ZT4-7 8.220205 8.220205 8.220205 ZT8-11 6.744775000000001 6.744775000000001 6.744775000000001 ZT12-15 9.020685 7.9850449999999995 10.056325000000001 ZT16-19 10.296585 10.296585 10.296585 ZT20-23 13.76575 13.76575 13.76575