condition mean min max ZT0-3 7.899942499999999 7.245505 8.554379999999998 ZT4-7 7.87326 7.87326 7.87326 ZT8-11 8.719475 8.719475 8.719475 ZT12-15 0 0 0 ZT16-19 10.953295 10.953295 10.953295 ZT20-23 10.95465 10.95465 10.95465