Thank you for your answers.
I have just replaced pdata.frame with plm.data and it worked.
tobit1<- plm.data(T1, index = c("firm", "year"))
But I have two more questions, maybe someone could help:
summary(Tob)
Call:
censReg(formula = Imp ~ Bath + CEOTurnover + ChangeOCF + E +
Sales + ROE + GTA + Size, data = tobit1, method = "BHHH")
Observations:
Total Left-censored Uncensored Right-censored
606 469 137 0
Coefficients:
Estimate Std. error t value Pr(> t)
(Intercept) 1.110e-03 5.648e-04 1.965 0.0494 *
Bath 7.442e-03 6.780e-03 1.098 0.2724
CEOTurnover -1.500e-03 2.742e-04 -5.472 4.45e-08 ***
ChangeOCF -6.738e-03 1.272e-03 -5.297 1.18e-07 ***
E -5.515e-02 5.304e-03 -10.398 < 2e-16 ***
Sales 8.009e-03 3.487e-04 22.971 < 2e-16 ***
ROE 2.921e-03 5.896e-06 495.331 < 2e-16 ***
GTA -3.509e-03 1.174e-03 -2.989 0.0028 **
Size -5.688e-04 1.220e-04 -4.662 3.13e-06 ***
logSigma -5.401e+00 2.746e-04 -19668.028 < 2e-16 ***
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
BHHH maximisation, 150 iterations
Return code 4: Iteration limit exceeded.
Log-likelihood: -66915.77 on 10 Df
How can I calculate McFadden's adjusted R2 in R?
How could I reduce iteration?
Thank you,
Vanessa
2017-01-04 13:25 GMT+01:00 PIKAL Petr <[email protected]>:
>
> Hi
>
> Although I cannot help you with your actual problem, you shall start with
> checking your data before doing any analysis. We do not have your data so it
> is hard to say what can be wrong. At least you shall provide result of
>
> str(T1) and/or
> str(mydata)
>
> The first message is not an error but a warning that tells you about coercing
> some log values to NaN which can result e.g. from negative values.
>
> log(-1)
> [1] NaN
> Warning message:
> In log(-1) : NaNs produced
>
> and probably some further calculation in summary function does not like it
> and throws error.
>
> But without data it is only a guess.
>
> And BTW, you shall post plain text not HTML.
>
> Cheers
> Petr
>
>
> > -----Original Message-----
> > From: R-help [mailto:[email protected]] On Behalf Of Vanessa
> > Romero
> > Sent: Wednesday, January 4, 2017 10:28 AM
> > To: [email protected]
> > Subject: [R] Tobit Regression with unbalanced Panel Data
> >
> > Hello,
> >
> > I am doing Tobit Regression in R, because my dependent variable is censored
> > at 0. I have unbalanced panel data, for 6 years, 107 companies. I use
> > package
> > CensReg.
> >
> > I have imported my database(T1).
> >
> > I use pdata.frame to specify the structure of my panel data. Like:
> >
> >
> > *mydata<- pdata.frame (T1, index = c("firm", "year")) *
> > Afterwards:
> >
> > *Tob <- censReg(formula=Imp ~ Bath + CEOTurnover + ChangeOCF + E +
> > Sales + ROE + GTA + Size , data = mydata, method="BHHH") * (as explained
> > here:
> > https://cran.r-project.org/web/packages/censReg/vignettes/censReg.pdf)
> >
> > I got here error message:
> >
> >
> > *Warnmeldung: In log(rEff$ercomp$sigma$id) : NaNs wurden erzeugt*
> >
> > Another error message when *summary(Tob)*
> >
> >
> >
> >
> >
> > *Call: censReg(formula = Imp ~ Bath + CEOTurnover + ChangeOCF + E + Sales
> > + ROE + GTA + Size, data = mydata, method = "BHHH") Observations: Total
> > Left-censored Uncensored Right-censored 606 469 137 0 Coefficients: Fehler
> > in printCoefmat(coef(x, logSigma = logSigma), digits = digits) : 'x' must be
> > coefficient matrix/data frame*
> >
> > I am new to statistics and to R, what could be the problem or would you
> > suggest using other package.
> >
> > Thank you,
> > Vanessa
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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