Re: [R] Correct statistical inference for linear regression models without intercept in R

2010-07-20 Thread StatWM
Thank you very much for your effort! But is there a measure, which can compare the goodness of fit of regression models with and without the intercept? Can I only compare them in terms of sum of squares residual? -- View this message in context: http://r.789695.n4.nabble.com/Correct-statistical

Re: [R] Correct statistical inference for linear regression models without intercept in R

2010-07-20 Thread peter dalgaard
On Jul 20, 2010, at 11:41 AM, StatWM wrote: > > Dear R community, > > is there a way to get correct t- and p-values and R squared for linear > regression models specified without an intercept? > > example model: > summary(lm(y ~ 0 + x)) > > This gives too low p-values and too high R squared.

Re: [R] Correct statistical inference for linear regression models without intercept in R

2010-07-20 Thread Dennis Murphy
Hi: On Tue, Jul 20, 2010 at 2:41 AM, StatWM wrote: > > Dear R community, > > is there a way to get correct t- and p-values and R squared for linear > regression models specified without an intercept? > > example model: > summary(lm(y ~ 0 + x)) > > This gives too low p-values and too high R squar

Re: [R] Correct statistical inference for linear regression models without intercept in R

2010-07-20 Thread Arun.stat
What x and y represent? Are they non-stationary, trending? then you would get very high R2 (~97-99%) and very low p-value. Perhaps you land on the world of spurious regression. In this case forcing intercept to zero would not help you. Work with differenced series instead raw data. Thanks and re

Re: [R] Correct statistical inference for linear regression models without intercept in R

2010-07-20 Thread StatWM
Let's assume x and y as stationary. It's not a spurious regression problem here. I think the function lm() has to have an intercept to give correct values of t- and p- and R squared. I wonder if you can correct the values in R though? -- View this message in context: http://r.789695.n4.nabble.co

[R] Correct statistical inference for linear regression models without intercept in R

2010-07-20 Thread StatWM
Dear R community, is there a way to get correct t- and p-values and R squared for linear regression models specified without an intercept? example model: summary(lm(y ~ 0 + x)) This gives too low p-values and too high R squared. Is there a way to correct it? Or should I specify with intercept t