condition mean min max ZT0-3 15.073386 15.073386 15.073386 ZT4-7 14.0930305 14.0930305 14.0930305 ZT8-11 15.357069 15.357069 15.357069 ZT12-15 17.7505145 17.7505145 17.7505145 ZT16-19 16.0069995 16.0069995 16.0069995 ZT20-23 15.628301 15.628301 15.628301