condition mean min max ZT0-3 6.77151 6.77151 6.77151 ZT4-7 4.047015 4.047015 4.047015 ZT8-11 6.7305 6.7305 6.7305 ZT12-15 5.990095 5.990095 5.990095 ZT16-19 10.764299999999999 10.764299999999999 10.764299999999999 ZT20-23 7.544465 7.544465 7.544465