Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread David Winsemius
Shouldn't this be similar (if not equivalent ) to examining the leverage or influence of z1 and z{n+1} in the full model of Y ~ beta*Z[1:(n+1)] ? -- David On Jan 27, 2012, at 7:46 PM, Michael wrote: > Yes, these observations are measured at equal-spaces... > > And the "n"-axis is the time

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Michael
Yes, these observations are measured at equal-spaces... And the "n"-axis is the time axis... Thank you! On Fri, Jan 27, 2012 at 3:54 PM, David Winsemius wrote: > > On Jan 27, 2012, at 4:10 PM, Michael wrote: > > I changed the notation for data from x to z... >> >> That's it. Should be very clear

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread David Winsemius
On Jan 27, 2012, at 4:10 PM, Michael wrote: I changed the notation for data from x to z... That's it. Should be very clear now... Thanks! Data: z1, z2, ..., z_{n+1} y1 = z_1,z_2,. z_n y2 = z_2, z_3,. z_{n+1} x1 = 1, ..., n x2 = 1, ..., n y1 = A1+ x1 * B1 + epsilon_1 y2 = A

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Mark Leeds
Hi: I don't think my paper applies because it needs the same y. Also, I don't think I follow what you're doing now ( now you have different y and different x's ? ) so I'd rather not comment but hopefully someone else does understand Good luck. On Fri, Jan 27, 2012 at 4:10 PM, Michael wrote: > I

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Michael
I changed the notation for data from x to z... That's it. Should be very clear now... Thanks! Data: z1, z2, ..., z_{n+1} y1 = z_1,z_2,. z_n y2 = z_2, z_3,. z_{n+1} x1 = 1, ..., n x2 = 1, ..., n y1 = A1+ x1 * B1 + epsilon_1 y2 = A2 + x2 * B2 + epsilon_2 H0: B1 and B2 are stati

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Mark Leeds
now i'm confused because you first use y_1, y_2 and then use y later. I would take a look at that earlier paper i mentioned. I think it's along the lines of what you want. Unfortunately. I don't have a computer copy of it. I got it from a library service where I once worked. mark On Fri, Jan 27,

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Michael
Thanks all. Here are a more clear statement of my question: Data: z1, z2, ..., z_{n+1} y1 = z_1,z_2,. z_n y2 = z_2, z_3,. z_{n+1} x1 = 1, ..., n x2 = 1, ..., n y = A1+ x1 * B1 + epsilon_1 y = A2 + x2 * B2 + epsilon_2 H0: B1 and B2 are statistically significally different...

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Mark Leeds
Hi Richard: I read michael's question as meaning that he says two univariate no intercept regression model where the predictor data is different in each model so that x1 = x_11,x_12,. x_1n x2 = x_21, x_22,. x_2n y = y_1, .y_n y = x1 * B1 + epsilon_1 y = x2 * B2 + epsilon_2 a

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-27 Thread Richard M. Heiberger
It looks like you might be asking for the anova() on two models. M1 <- lm(y ~ x1 + x2 + x3, data=something) M2 <- lm(y ~ x2 + x3, data=something) anova(M1, M2) Please send a reproducible example to the list if more detail is needed. Rich On Thu, Jan 26, 2012 at 11:59 PM, Michael wrote:

Re: [R] Is there a R command for testing the difference of two liear regressions?

2012-01-26 Thread Mark Leeds
I don't know what is available in R but a relevant paper that provides a test is by Hotelling, H ( September, 1940 ) "The Selection of Variates For Use in Prediction With Some Comments On The General Problem of Nuisance Parameters". Annals of Mathematical Statistics, 11, 271-283. On Thu, Ja

[R] Is there a R command for testing the difference of two liear regressions?

2012-01-26 Thread Michael
Hi al, I am looking for a R command to test the difference of two linear regressoon betas. Lets say I have data x1, x2...x(n+1). beta1 is obtained from regressing x1 to xn onto 1 to n. beta2 is obtained from regressing x2 to x(n+1) onto 1 to n. Is there a way in R to test whether beta1 and