condition mean min max ZT0-3 8.7656575 8.309995 9.22132 ZT4-7 10.638285 10.638285 10.638285 ZT8-11 16.959600000000002 16.959600000000002 16.959600000000002 ZT12-15 0 0 0 ZT16-19 24.014049999999997 24.014049999999997 24.014049999999997 ZT20-23 17.071649999999998 17.071649999999998 17.071649999999998