condition mean min max ZT0-3 15.23275 15.08395 15.38155 ZT4-7 16.22345 16.22345 16.22345 ZT8-11 17.784100000000002 17.784100000000002 17.784100000000002 ZT12-15 0 0 0 ZT16-19 20.7376 20.7376 20.7376 ZT20-23 18.72905 18.72905 18.72905