Re: [R] 95% Q-Q Plot error message

2012-11-04 Thread liang . che
Thanks John. I have one observation data point with a value that's exactly equal to the predicted value, therefore the residual is 0. Would this be the reason you mentioned below? From: "John Fox" To: Liang Che/US/TLS/PwC@Americas-US Cc: "'Sanford We

[R] Fw: 95% Q-Q Plot error message

2012-11-04 Thread liang . che
Can someone please help with the below - thanks! Warning messages: 1: Not plotting observations with leverage one: 7 2: Not plotting observations with leverage one: 7 > print(qqPlot(fit),envelop=.95); Error in model.frame.default(formula = Y ~ X - 1, drop.unused.levels = TRUE) : variable lengt

[R] Q-Q Plot error message

2012-11-04 Thread liang . che
Can someone please help with the error message below -- thanks! Warning messages: 1: Not plotting observations with leverage one: 7 2: Not plotting observations with leverage one: 7 > print(qqPlot(fit),envelop=.95); Error in model.frame.default(formula = Y ~ X - 1, drop.unused.levels = TRUE) :

[R] 95% Q-Q Plot error message

2012-11-04 Thread liang . che
Can someone please help with the error message below? Warning messages: 1: Not plotting observations with leverage one: 7 2: Not plotting observations with leverage one: 7 > print(qqPlot(fit),envelop=.95); Error in model.frame.default(formula = Y ~ X - 1, drop.unused.levels = TRUE) : variable

[R] How to write out this regression equation in R?

2012-10-09 Thread liang . che
For example: How to make R write out: Balance = 2 + 3 * IntGDP + 5 * IntUnemployment + 0.3 * d1 from the table below: Balance Intercept IntGDP GDPNum IntUnemployment IntInflationd1 d2 d3 3 2 3 5 0.3 0 0

Re: [R] why does R stepAIC keep unsignificant variables?

2012-10-09 Thread liang . che
will add() or drop() function work more similarly as SAS? I understand that there are not many observation points which might cause the problem, but why can the automated process run successfully in SAS instead? From: David Winsemius To: Liang Che/US/TLS/PwC@Americas-US Cc: Date

Re: [R] How to use Lines function to draw the error bars?

2012-10-08 Thread liang . che
one extra question How do I export the final image (with plots and lines added) into files in a batch mode for a bunch of regressions? thanks - Forwarded by Liang Che/US/TLS/PwC on 10/08/2012 08:48 PM - From: Liang Che/US/TLS/PwC To: Joseph Clark @INTL Cc: r-help@r

Re: [R] How to use Lines function to draw the error bars?

2012-10-08 Thread liang . che
thank you all for your answers i have figured out the plot i wanted - it was actually pretty easy lines(x=20:34,prd[,1],col="red",Ity=1) lines(x=20:34,prd[,2],lty=2) lines(x=20:34,prd[,3],lty=2) From: Joseph Clark To: Liang Che/US/TLS/PwC@Americas-US Cc: Date: 10/

[R] why does R stepAIC keep unsignificant variables?

2012-10-08 Thread liang . che
Ran a bunch of variables in R and the final result of StepAIC is as below: Why are the first 5 variables kept in the stepwise result?? Are the last 4 variables finally chosen after Stepwise? Thanks Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 1.315e-01 2.687e-01 0.490 0.6361

Re: [R] How to use Lines function to draw the error bars?

2012-10-08 Thread liang . che
- x : the condition has length > 1 and only the first element will be used From: Joseph Clark To: Liang Che/US/TLS/PwC@Americas-US Cc: Date: 10/08/2012 05:06 PM Subject:RE: [R] How to use Lines function to draw the error bars? In my example code, 'fit'

Re: [R] How to use Lines function to draw the error bars?

2012-10-08 Thread liang . che
From: Joseph Clark To: Liang Che/US/TLS/PwC@Americas-US, Date: 10/08/2012 04:03 PM Subject:RE: [R] How to use Lines function to draw the error bars? I typically use the function "plotCI" from the "plotrix" package for confidence intervals or error bars

Re: [R] How to use Lines function to draw the error bars?

2012-10-08 Thread liang . che
Thanks -- I got this message: Error in stripchart.default(x1, ...) : invalid plotting method From: Bita Shams To: Liang Che/US/TLS/PwC@Americas-US Date: 10/08/2012 03:41 PM Subject:Re: [R] How to use Lines function to draw the error bars? try this : plot(new,prd[,3

[R] time series data failing ncv test

2012-10-08 Thread liang . che
For a set of data showing seasonality (related to the 4th quarter), ncv test in R shows p-value of 0.008 which rejects the null hypothesis of constant-variance. How to apply White's standard error in R? thanks __ The i

[R] How to use Lines function to draw the error bars?

2012-10-08 Thread liang . che
fit lwrupr 1 218.4332 90.51019 346.3561 2 218.3906 90.46133 346.3198 3 218.3906 90.46133 346.3198 4 161.3982 44.85702 277.9394 5 192.4450 68.39903 316.4909 6 179.8056 56.49540 303.1158 7 219.5406 91.52707 347.5542 8 162.6761 46.65760 278.6945 9 193.8506 70.59

[R] time series data failing non-constant variance test

2012-10-08 Thread liang . che
For a set of data showing seasonality (related to the 4th quarter), ncv test shows p-value of 0.008 which rejects the null hypothesis of constant-variance. Currently a linear LM relationship is being applied to the data. Should white's error be used to correct the non-cons

[R] can stepAIC be customized to exclude coefficients with p-value less than certain values?

2012-10-04 Thread liang . che
For example, if coefficient's p-value is less than 0.1 I want the stepwise to automatically drop that variable. Can the stepAIC be customized to do that? SAS seems to be able to customized stepwise function with p-value or cooks'd. thanks!

[R] Error in if (any(ch)) { : missing value where TRUE/FALSE needed

2012-10-03 Thread liang . che
Can someone please help with the error message below? thanks! Start: AIC=-Inf value ~ 1 + Core_CPI__ + GDP_change + Unemployment + housing + interest + S_P + d1 + d2 + d3 Error in if (any(ch)) { : missing value where TRUE/FALSE needed In addition: Warning message: attempting model select

[R] will 9 data points work for a regression in R?

2012-10-03 Thread liang . che
See error message below: can someone please help with this? Thanks! Residuals: ALL 9 residuals are 0: no residual degrees of freedom! Residual standard error: NaN on 0 degrees of freedom Multiple R-squared: 1, Adjusted R-squared: NaN F-statistic: NaN on 8 and 0 DF, p-value: NA

[R] stepAIC in R

2012-10-03 Thread liang . che
My stepAIC function works for one set of data but not anotherone set of data shows the steps of eliminating variables, versus another set of data doesn't throw away any variables. Can anyone please explain why? Thanks __ T