[R] Exact p-values in lm() - rounding problem

[Ben Bolker]

Torvon <torvon <at> gmail.com> writes:

> 
> Thank you, Uwe.
> 
> summary(m1) gives me p-value estimates of:
> (Intercept) 2e-16
> x1 6.9e-15
> x2 1.9e-07
> x3 2.7e-09
> 
> While coef(summary(m1))[,4] gives me:
> (Intercept) 3.0e-23
> x1 5.7e-13
> x2 2.6e-07
> x3 1.7e-17
> 
> While the first one confirms my suspicion (-23 instead of -16), the latter
> one vary drastically (especially x3 from -09 to -17). Why is that?

  This looks fishy.  Could we please have a reproducible example?
For example, give us the results of dput(summary(m1)) ...

When I try this with example("lm") it works fine:

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    

> coef(summary(lm.D9))[,4]
 (Intercept)     groupTrt 
9.547128e-15 2.490232e-01