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

2013-02-12 Thread Torvon
I need to report exact p-values in my dissertation. Looking at my lm() results of many regressions with huge datasets I have the feeling that p-values are rounded to the smallest value of 2e-16, because this p-value is very common. Is that true or just chance? If it is true, how do I obtain the

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

2013-02-12 Thread Uwe Ligges
On 12.02.2013 13:37, Torvon wrote: I need to report exact p-values in my dissertation. Looking at my lm() results of many regressions with huge datasets I have the feeling that p-values are rounded to the smallest value of 2e-16, because this p-value is very common. Is that true or just

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

2013-02-12 Thread Torvon
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

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

2013-02-12 Thread 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

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

2013-02-12 Thread Uwe Ligges
On 12.02.2013 14:44, Torvon wrote: 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

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

2013-02-12 Thread Torvon
The code is quite long because I am running a WLS regression instead of an OLS regression (due to heteroscedasticity). First, I get mean structure, then get mean/SD relationship, then improve the variance structure by using weights proportional to 1/variance. I am quite sure this is not relevant,

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

2013-02-12 Thread Uwe Ligges
On 12.02.2013 15:15, Torvon wrote: The code is quite long because I am running a WLS regression instead of an OLS regression (due to heteroscedasticity). First, I get mean structure, then get mean/SD relationship, then improve the variance structure by using weights proportional to 1/variance.

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

2013-02-12 Thread Torvon
I'm sorry, no clue how I did not see that. Thank you! On 12 February 2013 15:21, Uwe Ligges lig...@statistik.tu-dortmund.dewrote: On 12.02.2013 15:15, Torvon wrote: The code is quite long because I am running a WLS regression instead of an OLS regression (due to heteroscedasticity).