Displaying 20 results from an estimated 6000 matches similar to: "Missing at random"
2010 Nov 25
2
Lifting Wavelet Transform
Hi R users
Thanks in advance
Is lifting wavelet transform implemented in R? If so, which package or codes can be used for performing that?
assaedi76@yahoo.com
Thanks
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2009 Nov 04
1
simulated data
R users. Thanks in advance.
I would be glad if someone could tell me how to get a simulated data from AR(1),
MA(1)
My email is : assaedi76@yahoo.com
Thanks
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2008 Mar 11
2
glm.fit: "fitted probabilities numerically 0 or 1 occurred"
Hi,
could anyone explain to me what this warning message
exactly means and what the consequences are?
Is it due to the fact that there are very extreme
observations / outliers included or what is the reason
for it?
Thanks so much,
Werner
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2010 Apr 04
2
logistic regression in an incomplete dataset
Dear all,
I want to do a logistic regression.
So far I've only found out how, in a dataset of complete cases.
I'd like to do logistic regression via max likelihood, using all the study
cases (complete and incomplete). Can you help?
I'm using glm() with family=binomial(logit).
If any covariate in a study case is missing then the study case is
dropped, i.e. it is doing a complete case
2010 Mar 12
2
find "CP"
R users
Thanks in advance:
I need to use the function "mle.cp" in R. When I run this function I recive
result <- mle.cp(y.hald~x.hald)
Error: could not find function "mle.cp"
could some one give me a help?
thanks
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2011 Jun 03
3
Not missing at random
Hello!
I would like to sample 30 % of cases (with at least 1 value lower than 3) and
among them I want to set all values lower than 3 (within selected cases) as NA
(NMAR- Not missing at random). I managed to sample cases, but I don’t know how
to set values (lower than 3) as NA.
R code:
x <-
2011 Feb 07
1
multiple imputation manually
Hi,
I want to impute the missing values in my data set multiple times, and then
combine the results (like multiple imputation, but manually) to get a mean
of the parameter(s) from the multiple imputations. Does anyone know how to
do this?
I have the following script:
y1 <- rnorm(20,0,3)
y2 <- rnorm(20,3,3)
y3 <- rnorm(20,3,3)
y4 <- rnorm(20,6,3)
y <- c(y1,y2,y3,y4)
x1 <-
2005 Nov 14
1
Little's Chi Square test for MCAR?
Hi.
Can anyone point me to any module in R which implements "Little's Chi
Square test" for MCAR.
The problem is that i have around 60 behavioural variables on a 6 point
categorical scale which i need to test for MCAR and MAR. What i can make
out from preliminary analysis is that moderate (0.30 to 0.60)
correlations may be present in several variable pairs leading me to
suspect
2007 Aug 31
2
memory.size help
I keep getting the 'memory.size' error message when I run a program I have
been writing. It always it cannot allocate a vector of a certain size. I
believe the error comes in the code fragement below where I have multiple
arrays that could be taking up space. Does anyone know a good way around
this?
w1 <- outer(xk$xk1, data[,x1], function(y,z) abs(z-y))
w2 <- outer(xk$xk2,
2008 Jul 29
3
finding a faster way to do an iterative computation
useR's,
I am trying trying to find out if there is a faster way to do a certain
computation. I have successfully used FOR loops and the apply function to
do this, but it can take some time to fully compute, but I was wondering if
anyone may know of a different function or way to do this:
> x
[1] 1 2 3 4 5
> xk
[1] 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
I want to do:
2011 May 16
2
conditional rowsums in sapply
Hi all
I have a data frame with duplicate columns and i want to remove duplicates
by adding rows in each group of duplicates, but have lots of NA's.
Data:
dfrm <- data.frame(a = 1:4, b= 1:4, cc= 1:4, dd=1:10, ee=1:4)
names(dfrm) <- c("a", "a", "b", "b", "b")
dfrm[3,2:3]<-NA
dfrm
a a b b b
1 1 1 1 1 1
2 2 2 2 2 2
3
2006 Aug 30
1
Optimization
Dear R-list,
I'm trying to estimate the relative importance of 6 environmental variables
in determining clam yield. To estimate clam yield a previous work used the
function Yield = (A^a*B^b*C^c...)^1/(a+b+c+...) where A,B,C... are the
values of the environmental variables and the weights a,b,c... have not been
calibrated on data but taken from literature. Now I'd like to estimate the
2007 Aug 28
1
alternate methods to perform a calculation
Consider a data frame (x) with 2 variables, x1 and x2, having equal values.
It looks like:
x1 x2
1 1
2 2
3 3
Now, consider a second data frame (xk):
xk1 xk2
0.5 0.5
1.0 0.5
1.5 0.5
2.0 0.5
0.5 1
1.0 1
1.5 1
2.0 1
0.5 1.5
1.0 1.5
1.5 1.5
2.0 1.5
0.5 2
1.0 2
1.5 2
2.0 2
I have written code to calculate some differences between these
2006 Mar 08
1
Want to fit random intercept in logistic regression (testing lmer and glmmML)
Greetings. Here is sample code, with some comments. It shows how I
can simulate data and estimate glm with binomial family when there is
no individual level random error, but when I add random error into the
linear predictor, I have a difficult time getting reasonable estimates
of the model parameters or the variance component.
There are no clusters here, just individual level responses, so
2001 Nov 21
2
distances from points to line
Dear all,
I have discovered that there are many things that I used to do in my GIS
which are easily done directly in R, for example calculating interpoint
distances using geoR and pick out points inside a polygon using splancs.
I now wonder, is there a function to create a line object like a
watercourse and then calculate the distances between many points in space
and this line?
I couldn't
2011 Jan 31
2
From data frame to list object
Dear all, let say I have following data frame:
> data.frame(x=rnorm(18), y=rep(c("a", "b", "c"), each=6))
x y
1 -1.072152537 a
2 0.382985265 a
3 0.058877377 a
4 -0.006911939 a
5 -2.355269051 a
6 -0.303095553 a
7 0.484038422 b
8 0.733928931 b
9 -1.136014346 b
10 0.503552090 b
11 1.708609658 b
12 -0.294599403 b
13
2010 Aug 30
1
New to R
I'm relatively new to R, and not particularly adept yet, but I was wondering
if there was a simply way to simulate missing data that are MAR, MNAR and
MCAR. I've got a good work-around for the MCAR data, but it's sort of hard
to work with.
Josh
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2013 Mar 06
2
Fwd: How to conditionally remove dataframe rows?
Hi,
I have a data frame with two columns. I need to remove duplicated rows in
first column, but I need to do it conditionally to values of the second
column.
Example:
Point_counts Psi_Sp
1 A 0
2 A 1
3 B 1
4 B 2
5 B 0
2011 Jul 15
3
summarized data set - how to use an "occurs" field
I have a data set with 22 fields and several thousand records in which
one field (count) indicates the number of times that each specific
combination of the other 21 fields occurred in a bigger and largely
unavailable data set.
So each record is unique in its combination of field values and has a
field that identifies how many multiples of this record actually
occurred.
Without resorting to
2012 Mar 18
3
Extracting numbers from a character variable of different types
Hello,
I have a file which contains a column with age, which is represented in the
two following patterns
1. "007/A" or ''007/a" or ''7 /a" ..... In this case A or a means year and I
would like to extract only the numeric values eg 7 in the above case if this
pattern exits in a line of file.
2. "004/M" or "004/m" where M or m means month