condition mean min max ZT0-3 8.9185775 8.324024999999999 9.51313 ZT4-7 7.412945 7.412945 7.412945 ZT8-11 9.952265 9.952265 9.952265 ZT12-15 0 0 0 ZT16-19 10.6527 10.6527 10.6527 ZT20-23 8.992609999999999 8.992609999999999 8.992609999999999