condition mean min max ZT0-3 0.959291 0.959291 0.959291 ZT4-7 0.67622 0.67622 0.67622 ZT8-11 0.566466 0.566466 0.566466 ZT12-15 0.8693845 0.8693845 0.8693845 ZT16-19 1.106605 1.106605 1.106605 ZT20-23 0.8975175 0.8975175 0.8975175