setwd("D:\\Rdownload\\lianxi\\second")  #设定工作路径
d2.3<-read.csv("ex2.3.csv", header = T)  #将ex2.3.csv数据读入到d2.3中
lm.exam<-lm(y~x1+x2+x3+x4+x5,data=d2.3)  #建立y关于x1,x2,x3,x4和x5的线性回归方程,数据为d2.3
summary(lm.exam)  #给出回归系数的估计和显著性检验等

## 
## Call:
## lm(formula = y ~ x1 + x2 + x3 + x4 + x5, data = d2.3)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -252.31  -48.18  -12.79   52.81  193.02 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)   
## (Intercept) -4.012e+02  1.431e+02  -2.803  0.01870 * 
## x1           1.444e-02  2.402e-02   0.601  0.56109   
## x2          -2.087e-02  8.657e-02  -0.241  0.81440   
## x3           5.810e-05  1.464e-03   0.040  0.96912   
## x4           3.044e+01  8.298e+00   3.668  0.00433 **
## x5           2.004e-01  1.115e-01   1.798  0.10235   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 129.6 on 10 degrees of freedom
## Multiple R-squared:  0.9879, Adjusted R-squared:  0.9818 
## F-statistic: 162.8 on 5 and 10 DF,  p-value: 3.043e-09