condition mean min max ZT0-3 6.162955 5.978285 6.347625 ZT4-7 5.107025 5.107025 5.107025 ZT8-11 4.59923 4.59923 4.59923 ZT12-15 0 0 0 ZT16-19 5.520284999999999 5.520284999999999 5.520284999999999 ZT20-23 6.11489 6.11489 6.11489