condition mean min max ZT0-3 19.589375 18.82775 20.351 ZT4-7 17.884050000000002 17.884050000000002 17.884050000000002 ZT8-11 14.61205 14.61205 14.61205 ZT12-15 0 0 0 ZT16-19 20.430349999999997 20.430349999999997 20.430349999999997 ZT20-23 19.85705 19.85705 19.85705