Displaying 20 results from an estimated 3000 matches similar to: "On p-values presented in the summary of Linear Models"
2012 Mar 02
1
indicating group numbers in a dendrogram
Hi,
Is it possible to place the group number in a cluster?
The best example I found was at
https://www.crops.org/images/publications/cs/42/5/1584f4.jpeg (see I, II,
IIIa, IIIb)
It would help to identify the group given by cutree since branches can turn
around and they necessarily are not plotted in order (group 2 is not
necessarily the second from the left).
Thanks for any help.
All the
2006 Aug 07
2
finding x values to meet a y
Hi,
I'd like to find which values of x will give me a y.
In other words, in the example of a gaussian curve, I want to find the values of
x that will give me a density, let's say, of 0.02.
curve(((1/(sqrt(2*pi)*10))*exp(-((x-50)^2)/(2*10^2))),xlim=c(0,100))
Thanks for any help,
Antonio Olinto
-------------------------------------------------
WebMail Bignet - O seu provedor do
2001 Sep 23
1
plot and lm (2)
Thanks for your reply Nassar.
What I really want is to overlay (like add=TRUE) the plots 1 and 2. With
plots "at the same screen" I meant overlaid and not one beside the other,
i.e., only one plot with all the points (1 to 10) in blue (or any other
color), the points 5 to 9 in red and a regression line from points 5 to 9.
Best regards,
Antonio Olinto
----- Original Message -----
2001 Sep 07
3
fitting models with gnls
Dear R-list members,
Some months ago I wrote a message on the usage of gnls (nlme library) and here I come again.
Let me give an example:
I have a 10 year length-at-age data set of 10 fishes (see growth.dat at the end of this message) and I want to fit a von Bertalanffy growth model, Li= Linf*(1-exp(-k*(ti-t0))) where Li = length at age i, Linf= asymptotic length, k= curvature parameter, ti=
2012 Dec 04
4
partial analisys of a time series
Dear list members
I want to analyze separately the months of a time series. In other words, I
want to plot and fit models for each month separately.
Taking the example of
http://a-little-book-of-r-for-time-series.readthedocs.org/en/latest/src/timeseries.html
births <- scan("http://robjhyndman.com/tsdldata/data/nybirths.dat")
birthstimeseries <- ts(births, frequency=12,
2001 Nov 09
2
ks.test
Dear R-List members,
I want to check if a set of measurements follows better a
gamma or a lognormal distribution (see data below).
Using shapiro.test I can test for normality (shapiro.test(log
(Lt)).
To test for gamma (and normal) distribution I would use
ks.test but I need to specify its shape and scale. How should
I calculate these values in R?
I tried
> Lt.fit <- glm(Lt ~ 1,
2011 Aug 31
2
VisualBasic "select case" commad in R
Hello
I'm translating a Visual Basic routine to R.
Which command in R is similar to "select case" in VB?
See the example:
select case int(AG)
case 0, 5, 8, 10
VAR = 37
case 1, 4
VAR = 70
case 3, 6, 9
VAR = 90
case 2, 7
VAR = 112
end select
A chain of "if else" would not be very elegant. Is there another option?
Thanks in advance. Best regards.
Antonio
2001 Sep 11
2
data frames
Dear R-list members
Here goes a question on data frames:
I want to create a new data frame excluding some records
(rows) from an existing one.
Considering the data frame "fish.dat" at the end of this
message, I can make a boxplot(Ring~Radius) and identify the
points at rows 11 and 25 as outliers.
With the command fish.dat[c(11, 25),] I can identify which
fishes are related to
2002 Jan 19
2
comma as decimal separator in plots
Hi,
Some time ago I asked about how to use comma as decimal separator in plots
and Mr. Paul Murrell wrote:
-------
You could try something with axis() and chartr(), like ...
par(mfrow=c(2,1))
plot(1:10/11, rep(1, 10), main="Standard X-Axis")
plot(1:10/11, rep(1, 10), main="Customised X-Axis", axes=F)
axis(1, at=pretty(1:10/11),
2001 Mar 28
4
fitting growth curves
Dear R-list members,
Cynthia M. Jones wrote a paper (Fitting growth curves to retrospective
size-at-age data, Fisheries Research 46(2000):123-129; abstract at
http://www.elsevier.nl/gej-ng/10/19/44/70/24/37/abstract.html)where the
SAS procedure MIXED, Macro NLINMIX (Littell et. al., 1996)was used to
estimate the von Bertalanffy growth function parameters assuming that
data from the same fish are
2000 Nov 05
3
glm
Hi to all,
So I'm also a new user. I downloaded the program last week and I think it's great. Thanks to those who have developed R.
I have a special interest in GLM as a tool to describe fisheries and its variables and I'm just begging to study it.
As I could understand there's two types of GLM sun of squares: in "type I" the factors are added in sequence and
2001 Sep 25
2
max-min plot
Hello R-list members,
I’m trying to make a min-avg-max plot (like a boxplot, without
box and outliers, i.e., for each class of "x" a vertical line
indicating the range (max-min) and an horizontal line or point
indicating the mean) with data like:
Year Avg Min Max
98 10 7 13
99 12 10 15
01 11 6 14
Which command should be used?
Many thanks,
Antonio Olinto
2008 Aug 22
1
Help on competing risk package cmprsk with time dependent covariate
Dear R users,
I d like to assess the effect of "treatment" covariate on a disease relapse risk with the package cmprsk.
However, the effect of this covariate on survival is time-dependent
(assessed with cox.zph): no significant effect during the first year of follow-up,
then after 1 year a favorable effect is observed on survival (step
function might be the correct way to say that ?).
2005 Jul 21
1
About object of class mle returned by user defined functions
Hi,
There is something I don't get with object of class "mle" returned by a
function I wrote. More precisely it's about the behaviour of method
"confint" and "profile" applied to these object.
I've written a short function (see below) whose arguments are:
1) A univariate sample (arising from a gamma, log-normal or whatever).
2) A character string
2009 Apr 15
2
AICs from lmer different with summary and anova
Dear R Helpers,
I have noticed that when I use lmer to analyse data, the summary function
gives different values for the AIC, BIC and log-likelihood compared with the
anova function.
Here is a sample program
#make some data
set.seed(1);
datx=data.frame(array(runif(720),c(240,3),dimnames=list(NULL,c('x1','x2','y'
))))
id=rep(1:120,2); datx=cbind(id,datx)
#give x1 a
2011 Mar 25
2
A question on glmnet analysis
Hi,
I am trying to do logistic regression for data of 104 patients, which
have one outcome (yes or no) and 15 variables (9 categorical factors
[yes or no] and 6 continuous variables). Number of yes outcome is 25.
Twenty-five events and 15 variables mean events per variable is much
less than 10. Therefore, I tried to analyze the data with penalized
regression method. I would like please some of the
2004 Jun 11
1
comparing regression slopes
Dear List,
I used rlm to calculate two regression models for two data sets (rlm
due to two outlying values in one of the data sets). Now I want to
compare the two regression slopes. I came across some R-code of Spencer
Graves in reply to a similar problem:
http://www.mail-archive.com/r-help at stat.math.ethz.ch/msg06666.html
The code was:
> df1 <- data.frame(x=1:10, y=1:10+rnorm(10))
2004 Dec 13
1
AIC, glm, lognormal distribution
I'm attempting to do model selection with AIC, using a glm and a lognormal
distribution, but:
fit1<-glm(BA~Year,data=pdat.sp1.65.04, family=gaussian(link="log"))
## gives the same result as either of the following:
fit1<-glm(BA~Year,data=pdat.sp1.65.04, family=gaussian)
fit1<-lm(BA~Year,data=pdat.sp1.65.04)
fit1
#Coefficients:
#(Intercept) Year2004
# -1.6341
2001 Nov 12
4
Doubt
As to call files of another softwares(as, Excel, minitab)
to be manipulated inside of R-plus?
Respectfully
Regiane
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2008 Jan 05
1
Likelihood ratio test for proportional odds logistic regression
Hi,
I want to do a global likelihood ratio test for the proportional odds
logistic regression model and am unsure how to go about it. I am using
the polr() function in library(MASS).
1. Is the p-value from the likelihood ratio test obtained by
anova(fit1,fit2), where fit1 is the polr model with only the intercept
and fit2 is the full polr model (refer to example below)? So in the
case of the