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 axis... > > Thank you! > On Fri, Jan 27, 2012 at 3:54 PM, David Winsemius <dwinsem...@comcast.net > > 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 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 statistically significally different... > > So in hopes of clarifying, ....So you want to test whether estimated > slopes are different after you slide a data-window one unit to the > right on the y-scale. Are you willing to say anything else about the > mathematical properties of Y? is it for instance measured at equal > time intervals? > > -- > > > > > > On Fri, Jan 27, 2012 at 2:41 PM, Mark Leeds <marklee...@gmail.com> > wrote: > > 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, 2012 at 3:35 PM, Michael <comtech....@gmail.com> > wrote: > > 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... > > Any more thoughts? > > Thanks a lot! > > On Fri, Jan 27, 2012 at 1:39 PM, Mark Leeds <marklee...@gmail.com> > wrote: > > 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 > > and he wants to see which coefficient ( B1 or B2 ) "works" better. > But I > could be wrong > which I only realized after reading your recommendation. michael: if > i'm > wrong, then disregard the paper reference that I sent earlier. > > > Mark > > > > On Fri, Jan 27, 2012 at 2:29 PM, Richard M. Heiberger > <r...@temple.edu>wrote: > > 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 <comtech....@gmail.com> > wrote: > > 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(nï¼1). > beta1 is obtained from regressing x1 to xn onto 1 to n. > > beta2 is obtained from regressing x2 to x(nï¼1) onto 1 to n. > > Is there a way in R to test whether beta1 and beta2 are statistically > different? > > Thanks a lot! > > [[alternative HTML version deleted]] > . > > David Winsemius, MD > West Hartford, CT > > David Winsemius, MD West Hartford, CT [[alternative HTML version deleted]]
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