condition mean min max ZT0-3 2.041405 2.041405 2.041405 ZT4-7 1.0384545 1.0384545 1.0384545 ZT8-11 1.8650449999999998 1.8650449999999998 1.8650449999999998 ZT12-15 1.660945 1.660945 1.660945 ZT16-19 1.8850850000000001 1.8850850000000001 1.8850850000000001 ZT20-23 2.14506 2.14506 2.14506