condition mean min max ZT0-3 253.924364 253.924364 253.924364 ZT4-7 509.61264700000004 509.61264700000004 509.61264700000004 ZT8-11 638.298993 638.298993 638.298993 ZT12-15 554.7303669999999 554.7303669999999 554.7303669999999 ZT16-19 420.079245 420.079245 420.079245 ZT20-23 288.874455 288.874455 288.874455