[交流] 【求助】SAS问题

> options(contrasts=c("contr.SAS", "contr.poly"))
> summary(lm(SOC ~ landform, soil))

Call:
lm(formula = SOC ~ landform, data = soil)

Residuals:
    Min      1Q  Median      3Q     Max
-0.6867 -0.6267 -0.1533  0.3608  1.2967

Coefficients:
                  Estimate Std. Error t value Pr(>|t|)   
(Intercept)         7.8967     0.3165  24.948 2.45e-10 ***
landformslopeland   2.0167     0.4476   4.505  0.00113 **
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 0.7753 on 10 degrees of freedom
Multiple R-squared: 0.6699,     Adjusted R-squared: 0.6369
F-statistic:  20.3 on 1 and 10 DF,  p-value: 0.001134

> summary(lm(SOC ~ landuse, soil))

Call:
lm(formula = SOC ~ landuse, data = soil)

Residuals:
   Min     1Q Median     3Q    Max
-1.685 -0.905  0.250  0.630  2.315

Coefficients:
                 Estimate Std. Error t value Pr(>|t|)   
(Intercept)        8.8950     0.5509  16.146 1.72e-08 ***
landusegrassland   0.0200     0.7791   0.026     0.98   
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 1.349 on 10 degrees of freedom
Multiple R-squared: 6.589e-05,  Adjusted R-squared: -0.09993
F-statistic: 0.0006589 on 1 and 10 DF,  p-value: 0.98

> anova(aov(SOC ~ landform, soil))
Analysis of Variance Table

Response: SOC
          Df  Sum Sq Mean Sq F value   Pr(>F)   
landform   1 12.2008 12.2008  20.297 0.001134 **
Residuals 10  6.0113  0.6011                    
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
> anova(aov(SOC ~ landuse, soil))
Analysis of Variance Table

Response: SOC
          Df  Sum Sq Mean Sq F value Pr(>F)
landuse    1  0.0012  0.0012   7e-04   0.98
Residuals 10 18.2109  1.8211               
> anova(aov(SOC ~ landform + landuse, soil))
Analysis of Variance Table

Response: SOC
          Df  Sum Sq Mean Sq F value   Pr(>F)   
landform   1 12.2008 12.2008 18.2706 0.002067 **
landuse    1  0.0012  0.0012  0.0018 0.967113   
Residuals  9  6.0101  0.6678                    
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1