condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 8.9844285 8.9844285 8.9844285 ZT8-11 8.262222000000001 8.262222000000001 8.262222000000001 ZT12-15 8.072845000000001 8.072845000000001 8.072845000000001 ZT16-19 7.656668 7.656668 7.656668 ZT20-23 8.852467 8.852467 8.852467