condition mean min max ZT0-3 2.558865 2.3777 2.74003 ZT4-7 2.59056 2.59056 2.59056 ZT8-11 2.102185 2.102185 2.102185 ZT12-15 0 0 0 ZT16-19 2.0848 2.0848 2.0848 ZT20-23 1.952275 1.952275 1.952275