Displaying 14 results from an estimated 14 matches similar to: "Help interpreting density()."
2010 Jan 22
2
sorted reshaping?
dear R wizards:? I am wrestling with reshape.? I have a long data set
that I want to convert into a wide data set, in which rows are firms
and columns are years.
> summary(rin)
firm fyear sim1
Min. :1004.00 Min. :1964.0 Min. : -1.00000
1st Qu.:1010.00 1st Qu.:1979.0 1st Qu.: -0.14334
Median :1016.00 Median :1986.0 Median : 0.00116
Mean
2012 Jul 09
1
anova.lm and F-test
Hello,
Why does anova.lm sometimes return a p-value and at other times not ? Is
it because it recognizes nested models from non-nested ones ?
> x<-seq(1,100,1)
> y<-3*x+rnorm(100)
> anova(lm(y~x),lm(y~x+I(x^2)),test="F")
Analysis of Variance Table
Model 1: y ~ x
Model 2: y ~ x + I(x^2)
Res.Df RSS Df Sum of Sq F Pr(>F)
1 98 90.449
2 97 90.288 1
2012 May 26
2
Assessing interaction effects in GLMMs
Dear R gurus
I am running a GLMM that looks at whether chimpanzees spend time in shade
more than sun (response variable 'y': used cbind() on counts in the sun and
shade) based on the time of day (Time) and the availability of shade
(Tertile). I've included some random factors too which are the chimpanzee
in question (Individual) and where they are in a given area (Zone). There
are
2010 Nov 25
1
coxph strange result
The following fit does not make sense to me, please, correct me if I have a logical error.
> moddowsn
Call:
coxph(formula = Surv(start, stop, resp) ~ sn + matfac2, data = coxsn1,
method = "efron")
coef exp(coef) se(coef) z p
sn2 0.0497 1.051 0.02030 2.450 1.4e-02
sn3 -0.0532 0.948 0.02038 -2.610 9.0e-03
sn4 -0.0410 0.960
2006 Apr 23
1
Question about bicreg
Dear Adrian and Ian (and r-helpers),
I encountered a curious result in developing an example using the bicreg
function in the BMA package: I noticed that pairs of models with equal R^2
and equal numbers of predictors had nevertheless different BIC values.
Looking at the bicreg function, the definition of BIC appears to be the
usual one, or close to it [bic <- n * log(1 - r2/100) + (size - 1) *
2007 Jun 01
2
how to specify starting values in varIdent() of lme()
I was reading the help but just did not get how to specify starting values for
varIdent() of the lme() function, although I managed to do it for corSymm().
Do I specify the values just as they are printed out in an output, like c(1,
1.3473, 1.0195). Or do I need to take the residual and multiply it with these
like c(0.2235, 0.2235*1.3473, 0.2235*1.0195)
or any other form that I dont know of?
2011 Feb 02
1
update not working
R-help,
I'm using the "update" command for a multiple regression model and it is
just not working:
> update(model1, . ~ . – temp:wind:rad,data=ozone.pollution)
Error: unexpected input in "model2<-update(model1, . ~ . –"
> summary(model1)
Call:
lm(formula = ozone ~ temp * wind * rad + I(rad^2) + I(temp^2) +
I(wind^2), data = ozone.pollution)
Residuals:
2012 Sep 11
4
Maintaining specific order when using aggregate or change order on axis
Hi All,
I'm using the following code to produce some stacked bar graphs.
*setwd("C:\\Users\\Tinus\\Documents\\NMMU\\R\\Seamounts")*
*SChla <- read.csv("SM_Chla_data.csv")*
*
*
*#Extract mean values from data file*
*
*
*Coral <- SChla[185:223,] #Reduce SChla to Coral only*
*coral <- with(Coral , aggregate(cbind(Pico, Nano, Micro),
list(Depth),FUN=mean))*
2012 Apr 20
1
predictOMatic for regression. Please try and advise me
I'm pasting below a working R file featuring a function I'd like to polish up.
I'm teaching regression this semester and every time I come to
something that is very difficult to explain in class, I try to
simplify it by writing an R function (eventually into my package
"rockchalk"). Students have a difficult time with predict and newdata
objects, so right now I'm
2004 Jun 11
4
Regression query
Hi
I have a set of data with both quantitative and categorical predictors.
After scaling of response variable, i looked for multicollinearity (VIF
values)
among the predictors and removed the predictors who were hinding some of the
other significant
predictors. I'm curious to know whether the predictors (who are not
significant)
while doing simple 'lm' will be involved in
2012 Jan 13
1
GLHT in multcomp: Two similar models, one doesn't work
i ran this model
> model2<-glm(rojos~ageandsex+sector+season+sector:season,quasipoisson)
> glht(model2,linfct=mcp(ageandsex="Tukey"))
General Linear Hypotheses
Multiple Comparisons of Means: Tukey Contrasts
Linear Hypotheses:
Estimate
M - H == 0 0.2898
SUB - H == 0 -0.2261
SUB - M == 0 -0.5159
I tried to do the same changing factor season
2004 Jun 11
1
Regression query : steps for model building
Hi
I have a set of data with both quantitative and categorical predictors.
After scaling of response variable, i looked for multicollinearity (VIF
values) among the predictors and removed the predictors who were hinding
some of the
other significant predictors. I'm curious to know whether the predictors
(who are not significant) while doing simple 'lm' will be involved in
2013 Mar 28
0
using cvlm to do cross-validation
Hello,
I did a cross-validation using cvlm from DAAG package but wasn't sure how to assess the result. Does this result means my model is a good model?
I understand that the overall ms is the mean of sum of squares. But is 0.0987 a good number? The response (i.e. gailRel5yr) has min,1st Quantile, median, mean and 3rd Quantile, and max as follows: (0.462, 0.628, 0.806, 0.896, 1.000, 2.400) ?
2011 Oct 06
1
Coefficients for lagged plm model variables not calculated
Hello,
So I am afraid I am having a recurring problem that I just can't figure out.
I am using the plm package to conduct a panel analysis - although I am not
sure if the problem is arising as a result of the plm package or something
more general.
I am trying to run a fixed effects model with effects over time and
individual. The model has various lags, and the problem is that these lags
do