Displaying 20 results from an estimated 3000 matches similar to: "Linear Model Prediction"
2012 Jul 06
3
estimating NA values against selected slots
Dear R Users,
Could you please help me on the following issue?
I have a real large yearly data set. For each year I have
365 flow values. Some of the flow values are not known and that’s why you will
see NA written in those slots. I wanted to know, is there a way that I can
estimate those values? I tried approx command but it seems least helpful for
the kind of issue I am up against.
2012 Nov 30
2
missed values
Hello
I have dataframe
101 2008-07 0.2898966
102 2008-08 0.3101667
103 2008-09 0.3730476
104 2008-10 0.2717037
105 2008-11 0.1344286
106 2008-12 0.1375000
107 2009-01 0.1781000
108 2009-02 0.2146667
109 2009-03 0.2808235
110 2009-04 0.4326250
111 2009-05 0.3420741
112 2009-06 0.2675238
113 2009-07 0.2478667
114 2009-08 0.3147000
115 2009-09 0.3437826
116 2009-10 0.2057391
117 2009-11 0.1824737
118
2013 Sep 02
1
Convert chr pieces to numbers that have specific values defined by 2 vectors
Dear all,
I think this is an easy task, but I don't know how to do it. Specifically, I have 69 columns with 300.000 rows. In each cell there is a code like
"2E3", "4RR", etc.
I now have a list that replaces this with values, e.g.,
old new
2E3 5
4RR 3
etc.
The list ist about 1600 rows long, so also to extensive for normal solutions
Do you how to do that? It would
2013 Sep 02
1
R dataframe and looping help
HI,
You may try this:
dat1<- read.table(text="
CustID TripDate Store Bread Butter Milk Eggs
1 2-Jan-12 a 2 0 2 1
1 6-Jan-12 c 0 3 3 0
1 9-Jan-12 a 3 3 0 0
1 31-Mar-13 a 3 0 0 0
2 31-Aug-12 a 0 3 3 0
2 24-Sep-12 a 3 3 0 0
2 25-Sep-12 b 3 0 0 0
",sep="",header=TRUE,stringsAsFactors=FALSE)
dat2<- dat1[,-c(1:3)]
res<- lapply(seq_len(ncol(dat2)),function(i)
2013 Feb 17
6
histogram
HI Elisa,
You could use ?cut()
vec1<-c(33,18,13,47,30,10,6,21,39,25,40,29,14,16,44,1,41,4,15,20,46,32,38,5,31,12,48,27,36,24,34,2,35,11,42,9,8,7,26,22,43,17,19,28,23,3,49,37,50,45)
label1<-unlist(lapply(mapply(c,lapply(seq(0,45,5),function(x) x),lapply(seq(5,50,5),function(x) x),SIMPLIFY=FALSE),function(i) paste(i[1],"<x<=",i[2],sep="")))
2013 Apr 29
4
expanding a presence only dataset into presence/absence
Hello,
I'm working with a very large dataset (250,000+ lines in its' current form)
that includes presence only data on various species (which is nested within
different sites and sampling dates). I need to convert this into a dataset
with presence/absence for each species. For example, I would like to expand
"My current data" to "Desired data":
My current data
2012 Dec 24
2
colmeans not working
[text file is also attached in case you find the format of email difficult to understand]
Dear useRs,You must all the planning for the christmas, but i am stucked in my office on the following issue
i had a file containg information about station name, year, month, day, and discharge information. i opened it by using
following command
> dat1<-read.table("EL.csv",header=TRUE,
2012 Jul 30
3
If/then statement, if in a list then
I need to write an if/then statement saying something along the lines of:
if (VALUE is in list) {...
How do I write that in R's language.
Thanks!
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2012 Jul 17
2
TRUE/FALSE
Any reason I'd get an error like this?
Error in if (round(pos[o + 1]) == (pos[o + 1] - 0.4)) { :
missing value where TRUE/FALSE needed
but when i do it individually, out of the for loop,
> (round(pos[o+1])==(pos[o+1]-.4) )
65
TRUE
--
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2012 Jul 18
1
Skip file
What i have is a for loop to name files. I want it to skip over the file if it doesn't exist. Is there a way to do that?
s=seq(from = chron("03/15/2012"), to = chron("06/15/2012"))
day=format(as.Date(s), "%Y%m%d")
for (k in 1:length(day)){
B1=read.csv(paste("S:/file_", day[k], ".csv", sep=""))
Date=strptime(B1[,1],
2009 Jan 28
1
gls prediction using the correlation structure in nlme
How does one coerce predict.gls to incorporate the fitted correlation
structure from the gls object into predictions? In the example below
the AR(1) process with phi=0.545 is not used with predict.gls. Is
there another function that does this? I'm going to want to fit a few
dozen models varying in order from AR(1) to AR(3) and would like to
look at the fits with the correlation structure
2013 Mar 18
1
try/tryCatch
Hi All,
I have tried every fix on my try or tryCatch that I have found on the
internet, but so far have not been able to get my R code to continue with
the "for loop" after the lmer model results in an error.
Here is two attemps of my code, the input is a 3D array file, but really
any function would do....
metatrialstry<-function(mydata){
a<-matrix(data=NA, nrow=dim(mydata)[3],
2003 Jul 30
2
Comparing two regression slopes
Hello,
I've written a simple (although probably overly roundabout) function to
test whether two regression slope coefficients from two linear models on
independent data sets are significantly different. I'm a bit concerned,
because when I test it on simulated data with different sample sizes and
variances, the function seems to be extremely sensitive both of these. I am
wondering if
2005 May 31
2
simple predict question
Excuse the simple question...
I'm not sure what I'm doing wrong with predict, but let me use this example:
Suppose I do:
dat<-matrix(c(0,0,10,20),2,byrow=T)
lm1<-lm(dat[,2]~dat[,1])
Suppose I want to generate the linearly-interpolated y-values between the
point (0,0) and (0,20) at every unit interval.
I thought I just do:
predict(lm1, data.frame(seq(0,10,1))) to get
2006 May 06
2
How to test for significance of random effects?
Dear list members,
I'm interested in showing that within-group statistical dependence is
negligible, so I can use ordinary linear models without including random
effects. However, I can find no mention of testing a model with vs.
without random effects in either Venable & Ripley (2002) or Pinheiro and
Bates (2000). Our in-house statisticians are not familiar with this,
either,
2005 Mar 09
1
multiple comparisons for lme using multcomp
Dear R-help list,
I would like to perform multiple comparisons for lme. Can you report to me
if my way to is correct or not? Please, note that I am not nor a
statistician nor a mathematician, so, some understandings are sometimes
quite hard for me. According to the previous helps on the topic in R-help
list May 2003 (please, see Torsten Hothorn advices) and books such as
Venables &
2013 May 01
2
significantly different from one (not zero) using lm
Hello,
I am work with a linear regression model:
y=ax+b with the function of lm.
y= observed migration distance of butterflies
x= predicted migration distance of butterflies
Usually the result will show
if the linear term a is significantly different from zero based on the
p-value.
Now I would like to test if the linear term is significantly different from
one.
(because I want to know
2010 Aug 17
2
how to selection model by BIC
Hi All:
the package "MuMIn" can be used to select the model based on AIC or AICc.
The code is as follows:
data(Cement)
lm1 <- lm(y ~ ., data = Cement)
dd <- dredge(lm1,rank="AIC")
print(dd)
If I want to select the model by BIC, what code do I need to use? And when
to select the best model based on AIC, what the differences between the
function "dredge" in
2006 Apr 14
5
vector-factor operation
I found myself wanting to average a vector [vec] within each level of a
factor [Fac], returning a vector of the same length as vec. After a
while I realised that
lm1 <- lm(vec ~ Fac)
fitted(lm1)
did what I want.
But there must be another way to do this, and it would be good to be
able to apply other functions than mean() in this way.
Cheers, Murray
--
Dr Murray Jorgensen
2006 Nov 30
1
data.frame within a function (PR#9294) (cont'd)
This continues the message "data.frame within a function (PR#9294)" that
was posted on 2006/10/12. Duncan Murdoch kindly replied. I'm using the
current version R 2.4.0, but the same issue exists. Just copy and paste
the following code under R, and compare the output of f1() and f2() and
the output of f3() and f4(). Does anybody have any idea? Thanks.