回复 第1楼 的 qxde01：
我也遇到这个问题，我猜可能是因为某一次下载的时候因为网络原因没有返回完整的数据，所以我又加了一步检测返回值，如果获取失败的话就再次尝试getURL。我加了这些以后暂时还没有报过错。
抛砖引玉，还请高手看看对不对。
</p><br /> a <- matrix(c(0.57002,1 ,<br /> 40.56,1 ,<br /> 7.8499,1 ,<br /> -36.91,1 ,<br /> -45.15,1 ,<br /> 6.2401,1 ,<br /> 4.79,1 ,<br /> 1.0899,1 ,<br /> -9.44,1 ,<br /> 6.54,1 ,<br /> -0.89008,1 ,<br /> -0.40994,1 ,<br /> 51.63,1 ,<br /> -27.76,1 ,<br /> 4.03,1 ,<br /> -31.86,1 ,<br /> 13.14,1 ,<br /> 14.37,1 ,<br /> 0.029999,1 ,<br /> -5.54,1 ,<br /> 0.029953,1 ,<br /> -7.6901,1 ,<br /> 5.4001,1 ,<br /> 10.49,1 ,<br /> -8.04,1 ,<br /> -4.51,1 ,<br /> 13.97,1 ,<br /> 12.53,1 ,<br /> 5.22,1 ,<br /> 55.93,1 ,<br /> -11.22,1 ,<br /> 14.22,1 ,<br /> 5.64,1 ,<br /> -19.3,1 ,<br /> -32.31,1 ,<br /> 2.6,1 ,<br /> 7.29,1 ,<br /> 7.4401,1 ,<br /> -18.49,1 ,<br /> 13.94,1 ,<br /> 4.04,1 ,<br /> 52.62,1 ,<br /> -9.86,1 ,<br /> 31.46,1 ,<br /> 3.2099,1 ,<br /> 3.73,1 ,<br /> -3.4,1 ,<br /> 8.76,1 ,<br /> -13.23,1 ,<br /> -3.0899,1 ,<br /> -4.9599,1 ,<br /> -18.34,1 ,<br /> -9.77,1 ,<br /> -4.6801,1 ,<br /> 6.1901,1 ,<br /> 0.63007,1 ,<br /> 19.79,1 ,<br /> 11.74,1 ,<br /> 19.33,1 ,<br /> 19.15,1 ,<br /> -18.1,1 ,<br /> 9.98,1 ,<br /> -12.29,1 ,<br /> -0.25995,1 ,<br /> -9.1901,1 ,<br /> 11.15,1 ,<br /> -34.51,1 ,<br /> -11.59,1 ,<br /> -27.59,1 ,<br /> 4.01,1 ,<br /> -6.3199,1 ,<br /> 1.3699,1 ,<br /> -0.26001,1 ,<br /> -15.23,1 ,<br /> -0.019989,1 ,<br /> 26.03,1 ,<br /> 17.03,1 ,<br /> -5.53,1 ,<br /> 0.52005,1 ,<br /> 4.7,1 ,<br /> -7.88,1 ,<br /> 8.24,1 ,<br /> -4.9299,1 ,<br /> -2.07,1 ,<br /> 40.99,1 ,<br /> 21.11,1 ,<br /> -1.5099,1 ,<br /> -17.84,1 ,<br /> -9.6501,1 ,<br /> -4.89,1 ,<br /> 41.97,1 ,<br /> -24.97,1 ,<br /> -47.3,1 ,<br /> -0.93008,1 ,<br /> -24.87,1 ,<br /> -2.3601,1 ,<br /> -8.4401,1 ,<br /> -14.77,0 ,<br /> -17.44,0 ,<br /> -7.21,0 ,<br /> -2.88,0 ,<br /> -22.5,0 ,<br /> 2.52,0 ,<br /> 1.7501,0 ,<br /> -31.26,0 ,<br /> -7.35,0 ,<br /> -1.01,0 ,<br /> -52.98,0 ,<br /> 8.76,0 ,<br /> 25.49,0 ,<br /> 3.17,0 ,<br /> -11.82,0 ,<br /> -14.19,0 ,<br /> -11.5,0 ,<br /> -36.15,0 ,<br /> 52.53,0 ,<br /> -6.1801,0 ,<br /> -42.32,0 ,<br /> -31.83,0 ,<br /> 12.57,0 ,<br /> -3.6499,0 ,<br /> -0.14996,0 ,<br /> -5.89,0 ,<br /> -2.4001,0 ,<br /> -3.62,0 ,<br /> -4.38,0 ,<br /> -23.12,0 ,<br /> -11.56,0 ,<br /> -19.25,0 ,<br /> 47.1,0 ,<br /> -20.03,0 ,<br /> 3.25,0 ,<br /> 3.9301,0 ,<br /> -10.02,0 ,<br /> -3.0299,0 ,<br /> -0.91005,0 ,<br /> -13.14,0 ,<br /> 22.4,0 ,<br /> -42.83,0 ,<br /> -16.93,0 ,<br /> -13.3,0 ,<br /> -46.04,0 ,<br /> -18.76,0 ,<br /> -10.35,0 ,<br /> -4.57,0 ,<br /> -4,0 ,<br /> 30.42,0 ,<br /> 14.13,0 ,<br /> -45.71,0 ,<br /> -1.24,0 ,<br /> -5.71,0 ,<br /> -43.42,0 ,<br /> 19.02,0 ,<br /> -17.34,0 ,<br /> 1.7801,0 ,<br /> -4.67,0 ,<br /> -10.11,0 ,<br /> -14.48,0 ,<br /> 2.9,0 ,<br /> -15.15,0 ,<br /> 42.03,0 ,<br /> 7.31,0 ,<br /> -2.3499,0 ,<br /> -7.08,0 ,<br /> 10.08,0 ,<br /> 11.01,0 ,<br /> 1.76,0 ,<br /> 0.9899,0 ,<br /> -8.89,0 ,<br /> 5.38,0 ,<br /> -23.42,0 ,<br /> -4.12,0 ,<br /> -36.98,0 ,<br /> -4.99,0 ,<br /> -4.9501,0 ,<br /> -3.8399,0 ,<br /> -17.52,0 ,<br /> -7.35,0 ,<br /> -1.04,0 ,<br /> -12.09,0 ,<br /> -23.92,0 ,<br /> 6.8499,0 ,<br /> -3.97,0 ,<br /> 42.43,0 ,<br /> -20.52,0 ,<br /> -14.3,0 ,<br /> -15.94,0 ,<br /> -0.95001,0 ,<br /> -37.38,0 ,<br /> -14.36,0 ,<br /> 14.97,0 ,<br /> -6.23,0 ,<br /> 39.93,0 ,<br /> -65.34,0 ,<br /> -27.15,0 ,<br /> -4,0 ,<br /> -10.05,0 ,<br /> 26.67,0 ,<br /> -9.9199,0 ,<br /> 12.66,0 ,<br /> 19.83,0 ,<br /> -44.88,0 ,<br /> 3.2799,0 ,<br /> -10.04,0 ,<br /> -30.55,0 ,<br /> -13.25,0 ,<br /> -8,0 ,<br /> -3.4199,0 ,<br /> -6.8201,0 ,<br /> 4.8102,0 ,<br /> -8.9901,0 ,<br /> -21.77,0 ,<br /> -5.92,0 ,<br /> 13.68,0 ,<br /> 11.1,0 ,<br /> -0.74997,0 ,<br /> 2.49,0 ,<br /> -4.98,0 ,<br /> -3.2399,0 ,<br /> -24.91,0 ,<br /> 12.24,0 ,<br /> 11.01,0 ,<br /> 10.66,0 ,<br /> -1.11,0 ,<br /> -67.97,0 ,<br /> -9.48,0 ,<br /> 11.76,0 ,<br /> 34.64,0 ,<br /> 0.55008,0 ,<br /> -5.89,0 ,<br /> -10.19,0 ,<br /> -11.82,0 ,<br /> -4.97,0 ,<br /> -4.6501,0 ,<br /> 12.61,0 ,<br /> -10.48,0 ,<br /> 7.4499,0 ,<br /> -16.77,0 ,<br /> -0.75005,0 ,<br /> 10.02,0 ,<br /> -7.41,0 ,<br /> -16.11,0 ,<br /> -21.22,0 ,<br /> -12.08,0 ,<br /> -8.1,0 ,<br /> -22.82,0 ,<br /> 32.078,0 ,<br /> 2.17,0 ,<br /> -13.95,0 ,<br /> 2.02,0 ,<br /> -7.1201,0 ,<br /> -73.18,0 ,<br /> -12.8,0 ,<br /> -3.09,0 ,<br /> 8.7801,0 ,<br /> 30.21,0 ,<br /> -24.06,0 ,<br /> -48.98,0 ,<br /> 0.82004,0 ,<br /> -15.36,0 ,<br /> -6.9,0 ,<br /> -14.56,0 ,<br /> 53.73,0 ,<br /> -38.96,0 ,<br /> -7.36,0 ,<br /> -38.24,0 ,<br /> -10.7,0 ,<br /> 42.76,0 ,<br /> -11.51,0 ,<br /> -1.44,0 ,<br /> 28.67,0 ,<br /> -10.37,0 ,<br /> -11.73,0 ,<br /> -5.9801,0 ,<br /> -0.67998,0 ,<br /> 2.3499,0 ,<br /> -24.25,0 ,<br /> -25.01,0 ,<br /> 6.06,0 ,<br /> 0.51004,0 ,<br /> 4.74,0 ,<br /> -2.9399,0 ,<br /> -28.58,0 ,<br /> -44.01,0 ,<br /> -69.09,0 ,<br /> -3.1,0 ,<br /> 12.81,0 ,<br /> -10.6,0 ,<br /> -5.2501,0 ,<br /> 15.41,0 ,<br /> -61.07,0 ), ncol=2, byrow=TRUE)</p> <p>x <- a[a[,2]==0, 1]<br /> y <- a[a[,2]==1, 1]<br /> plot(density(x))<br /> lines(density(y))<br /> t.test(x,y)<br />我试了一下，从图片上看两组的分布是有区别的，均值看上去不一样