Displaying 20 results from an estimated 700 matches similar to: "Durban Watson statistics"
2004 Jul 21
2
Testing autocorrelation & heteroskedasticity of residuals in ts
Hi,
I'm dealing with time series. I usually use stl() to
estimate trend, stagionality and residuals. I test for
normality of residuals using shapiro.test(), but I
can't test for autocorrelation and heteroskedasticity.
Is there a way to perform Durbin-Watson test and
Breusch-Pagan test (or other simalar tests) for time
series?
I find dwtest() and bptest() in the package lmtest,
but it
2010 Sep 24
3
bptest
Hi
I'm very new to R but have plenty of experience with statistics and other
packages like SPSS, SAS etc.
I have a dataset of around 20 columns and 200 rows. I'm trying to fit a
very simple linear model between two variables. Having done so, I want to
test the model for heteroscedasticity using the Breusch-Pagan test.
Apparently this is easy in R by simply doing
bptest(modelCH,
2009 Oct 16
1
Breusch-pagan and white test - check homoscedasticity
Hi r-programmers,
I performe Breusch-Pagan tests (bptest in package lmtest) to check the
homoscedasticity of the residuals from a linear model and I carry out carry
out White's test via
bptest (formula, ~ x * z + I(x^2) + I(z^2)) include all regressors and the
squares/cross-products in the auxiliary regression.
But what can I do if I want find coefficient and p-values of variables x, z,
x*z,
2012 Sep 18
1
Contradictory results between different heteroskedasticity tests
Hi all,
I'm getting contradictory results from bptest and ncvTest on a model
calculated by GLS as:
olslm = lm(log(rr)~log(aloi)*reg*inv, data)
varlm = lm(I(residuals(olslm)^2)~log(aloi)*reg*inv, data)
glslm = lm(log(rr)~log(aloi)*reg*inv, data, weights=1/fitted(varlm))
Testing both olslm and glslm with both ncvTest and bptest gives:
> ncvTest(olslm)
Non-constant Variance Score Test
2005 Jun 04
1
the test result is quite different,why?
data:http://fmwww.bc.edu/ec-p/data/wooldridge/CRIME4.dta
> a$call
lm(formula = clcrmrte ~ factor(year) + clprbarr + clprbcon +
clprbpri + clavgsen + clpolpc, data = cri)
> bptest(a,st=F)
Breusch-Pagan test
data: a
BP = 34.4936, df = 10, p-value = 0.0001523
> bptest(a,st=T)
studentized Breusch-Pagan test
data: a
BP = 10.9297, df = 10, p-value = 0.363
>
2009 Sep 18
1
some irritation with heteroskedasticity testing
Dear all,
Trying to test for heteroskedasticity I tried several test from the
car package respectively lmtest. Now that they produce rather
different results i am somewhat clueless how to deal with it.
Here is what I did:
1. I plotted fitted.values vs residuals and somewhat intuitively
believe, it isn't really increasing...
2. further I ran the following tests
bptest (studentized
2012 Oct 13
2
White test
Hello,
Is there a way to perform a White test (testing heteroscedasticity) under R?
Best regards,
Afrae Hassouni
2016 Apr 04
4
Test for Homoscedesticity in R Without BP Test
Respected Sir,
I am doing a project on multiple linear model fitting and in that project I
have to test Homoscedesticity of errors I have google for the same and
found bptest for the same but in R version 3.2.4 bp test is not available.
So please suggest me a test on homoscedesticity ASAP as we have to submit
our report on 7-04-2016.
P.S. : I have plotted residuals against fitted values and it is
2011 Jan 20
2
Regression Testing
I'm new to R and some what new to the world of stats. I got frustrated
with excel and found R. Enough of that already.
I'm trying to test and correct for Heteroskedasticity
I have data in a csv file that I load and store in a dataframe.
> ds <- read.csv("book2.csv")
> df <- data.frame(ds)
I then preform a OLS regression:
> lmfit <- lm(df$y~df$x)
To
2016 Apr 04
1
Test for Homoscedesticity in R Without BP Test
On Mon, 4 Apr 2016, varin sacha via R-help wrote:
> Hi Deepak,
>
> In econometrics there is another test very often used : the white test.
> The white test is based on the comparison of the estimated variances of
> residuals when the model is estimated by OLS under the assumption of
> homoscedasticity and when the model is estimated by OLS under the
> assumption of
2016 Apr 04
0
Test for Homoscedesticity in R Without BP Test
Hi Deepak,
In econometrics there is another test very often used : the white test.
The white test is based on the comparison of the estimated variances of residuals when the model is estimated by OLS under the assumption of homoscedasticity and when the model is estimated by OLS under the assumption of heteroscedastic.
The White test with R
install.packages("bstats")
library(bstats)
2004 Jan 13
3
How can I test if a not independently and not identically distributed time series residuals' are uncorrelated ?
I'm analizing the Argentina stock market (merv)
I download the data from yahoo
library(tseries)
Argentina <- get.hist.quote(instrument="^MERV","1996-10-08","2003-11-03", quote="Close")
merv <- na.remove(log(Argentina))
I made the Augmented Dickey-Fuller test to analyse
if merv have unit root:
adf.test(merv,k=13)
Dickey-Fuller = -1.4645,
2007 May 30
1
white test to check homoscedasticity of the residuals
Hi R-programmers,
I can't find find the White test to check the homoscedasticity of the
residuals from a linear model. Could you please help me with this?
Thank you !
BC
[[alternative HTML version deleted]]
2010 Dec 22
1
tests on polr object
Using ordered probit model, I get errors from dwt and bptest.
dwt:
Error in durbinWatsonTest.default(...) : requires vector of residuals
bptest:
Error in storage.mode(y) <- "double" :
invalid to change the storage mode of a factor
I imagine I have to restate as an individual probit model for each category,
but is there an easier way?
thanks,
bp
[[alternative HTML version
2011 Feb 11
3
Prueba de homocedasticidad
Buen dia!!
Pues me encuentro trabajando con un conjunto de datos simulados que se ajustan a un modelo Ar(1) y pues queria saber si existe un comando para realizarle una prueba de homocedasticidad, pues la prueba que hay en el R es la bartlett.test pero pues no estoy muy seguro para usarla.
Gracias
[[alternative HTML version deleted]]
2009 Aug 03
1
Comparison of Output from "dwtest" and "durbin.watson"
Should "dwtest" and "durbin.watson" be giving me the same DW statistic and
p-value for these two fits?
library(lmtest)
library(car)
X <- c(4.8509E-1,8.2667E-2,6.4010E-2,5.1188E-2,3.4492E-2,2.1660E-2,
3.2242E-3,1.8285E-3)
Y <- c(2720,1150,1010,790,482,358,78,35)
W <- 1/Y^2
fit <- lm(Y ~ X - 1)
dwtest(fit,alternative="two.sided")
2002 Apr 19
4
Durbin-Watson test in packages "car" and "lmtest"
Hi,
P-values in Durbin-Watson test obtained through the use of functions available in packages "lmtest" and "car" are different. The difference is quite significant. function "dwtest" in "lmtest" is much faster than "burbinwatson" in "car". Actually, you can take a nap while the latter trying to calculated Durbin-Watson test. My question
2006 Sep 29
6
List-manipulation
Hi,
Sorry for the question, I know it should be basic knowledge but I'm
struggling for two hours now.
How do I select only the first entry of each list member and ignore the
rest?
So for
> $"121_at"
> -113691170
> $"1255_g_at"
> 42231151
> $"1316_at"
> 35472685 35472588
> $"1320_at"
> -88003869
2011 Jun 08
1
Autocorrelation in R
Hi,
I am trying to learn time series, and I am attending a colleague's
course on Econometrics. However, he uses e-views, and I use R. I am
trying to reproduce his examples in R, but I am having problems
specifying a AR(1) model. Would anyone help me with my code?
Thanks in advance!
Reproducible code follows:
download.file("https://sites.google.com/a/proxima.adm.br/main/ex_32.csv
2011 Aug 12
1
Which Durbin-Watson is correct? (weights involved) - using durbinWatsonTest and dwtest (packages car and lmtest)
Hello!
I have a data frame mysample (sorry for a long way of creating it
below - but I need it in this form, and it works). I regress Y onto X1
through X11 - first without weights, then with weights:
regtest1<-lm(Y~., data=mysample[-13]))
regtest2<-lm(Y~., data=mysample[-13]),weights=mysample$weight)
summary(regtest1)
summary(regtest2)
Then I calculate Durbin-Watson for both regressions