condition mean min max ZT0-3 521.453945 521.453945 521.453945 ZT4-7 439.23777199999995 439.23777199999995 439.23777199999995 ZT8-11 473.40413250000006 473.40413250000006 473.40413250000006 ZT12-15 521.944433 521.944433 521.944433 ZT16-19 576.1133585 576.1133585 576.1133585 ZT20-23 690.8805070000001 690.8805070000001 690.8805070000001