condition mean min max ZT0-3 6.947818303083333 6.730417276500001 7.165219329666666 ZT4-7 5.952550225166666 5.777163335333333 6.127937115 ZT8-11 8.378554097 7.9963103890000005 8.760797805 ZT12-15 9.273081811666666 9.238168266333332 9.307995357 ZT16-19 12.346008963 12.07338162 12.618636305999999 ZT20-23 11.862087801166666 10.910054691 12.814120911333333