[R] Extract statistics from lm()

[Albyn Jones]

Look at the data structure produced by summary()

> names(summary(lm.D9))
  [1] "call"          "terms"         "residuals"     "coefficients"
  [5] "aliased"       "sigma"         "df"            "r.squared"
  [9] "adj.r.squared" "fstatistic"    "cov.unscaled"

Now look at the data structure for the coefficients in the summary:

> summary(lm.D9)$coefficients
             Estimate Std. Error   t value     Pr(>|t|)
(Intercept)    5.032  0.2202177 22.850117 9.547128e-15
groupTrt      -0.371  0.3114349 -1.191260 2.490232e-01

> class(summary(lm.D9)$coefficients)
[1] "matrix"

> summary(lm.D9)$coefficients[,3]
(Intercept)    groupTrt
   22.850117   -1.191260

albyn

Quoting Bogaso <bogaso.christofer at gmail.com>:

>
> Hi, perhaps this question was answered previously however I could not find
> them. My problem is how how to extract a particular statistic from the
> result given by lm(). For e.g.
>
> ctl <- c(4.17,5.58,5.18,6.11,4.50,4.61,5.17,4.53,5.33,5.14)
> trt <- c(4.81,4.17,4.41,3.59,5.87,3.83,6.03,4.89,4.32,4.69)
> group <- gl(2,10,20, labels=c("Ctl","Trt"))
> weight <- c(ctl, trt)
>> summary(lm.D9 <- lm(weight ~ group))
>
> Call:
> lm(formula = weight ~ group)
>
> Residuals:
>     Min      1Q  Median      3Q     Max
> -1.0710 -0.4938  0.0685  0.2462  1.3690
>
> Coefficients:
>             Estimate Std. Error t value Pr(>|t|)
> (Intercept)   5.0320     0.2202  22.850 9.55e-15 ***
> groupTrt     -0.3710     0.3114  -1.191    0.249
> ---
> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
>
> Residual standard error: 0.6964 on 18 degrees of freedom
> Multiple R-squared: 0.07308,    Adjusted R-squared: 0.02158
> F-statistic: 1.419 on 1 and 18 DF,  p-value: 0.249
>
>
> Here I want to extract the values of "t-stat", "Pr(>|t|)" individually. Can
> anyone please guide me how to get them?
> --
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