Displaying 20 results from an estimated 12000 matches similar to: "sequences"
2007 Jul 05
3
Loop and function
Hi All, I am trying to make a loop for a function and I am using the
following codes. "p" and "var" are some matrix obtained before. I would like
to apply the function "gpdlow" for i in 1:12 and get the "returnlow" for i
in 1:12. But when I ask for "returnlow" there are warnings and it turns out
some strange result.
for (i in 1:12){
gpdlow
2007 Oct 02
5
Linear Regression
Hello,
I would like to fit a linear regression and when I use summary(), I got the
following result:
Call:
lm(formula = weight ~ group - 1)
Residuals:
Min 1Q Median 3Q Max
-1.0710 -0.4938 0.0685 0.2462 1.3690
Coefficients:
Estimate Std. Error t value Pr(>|t|)
groupCtl 5.0320 0.2202 22.85 9.55e-15 ***
groupTrt 4.6610 0.2202 21.16 3.62e-14
2007 Jun 19
2
Histogram
Hello, I am using the following codes to plot a histogram and density line
for x. For the density line, I just want it to show the two tails, eg, for x
larger than 0.05 ans smaller than -0.05
hist (x, seq(-0.1,0.1,0.01),freq = FALSE)
lines (density(x,bw="SJ"), x> 0.05 & x< (-0.05), col = "red")
But is does not work, can anyone give me some advice?
--
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2007 Dec 03
2
Linear Regression, Data is a list
Hello,
I would like to perform a linear regression and the data is a list.e.g
lm(list$abc~., data=list) or lm(abc~., data=list), which would give the same
result.
The problem is I would like to call the response variable in a more general
form. What I try to achieve is sth like lm(list$(paste("a","b","c"))~.,
data=list), but it does not work.
Could anyone give me
2007 Jun 19
2
Function -return value
Hi, I am trying to write a function with the following codes and I would like
it to return the values for "alpha
beta para parab " seperately. Then I would like to use this funstion for
"variable" with factor "a" and "b". But the result turns out to be a matrix
with element like "Numeric,2" ... I guess they are just the values for
2007 Jul 10
3
ECDF, distribution of Pareto, distribution of Normal
Hello all,
I would like to plot the emperical CDF, normal CDF and pareto CDF in the
same graph and I amusing the following codes. "z" is a vector and I just
need the part when z between 1.6 and 3.
plot(ecdf(z), do.points=FALSE, verticals=TRUE,
xlim=c(1.6,3),ylim=c(1-sum(z>1.6)/length(z), 1))
x <- seq(1.6, 3, 0.1)
lines(x,pgpd(x, 1.544,0.4373,-0.2398), col="red")
y
2007 Jun 29
2
cbind
Hi, I have a series of return data, a and b are factors. I would like to
build a matrix which contains each vector of "returns". I am thinking about
something as following, but I guess there should be a sensible way of doing
this.
returns <- split(return, list(regimef, assetf))
cbind(returns[[1]], returns[[2]],...,returns[[n]])
Could anyone give me some advice? Many thanks.
--
2007 Sep 17
2
vector name
I have got a list named "filtered", I would like to construct alist named
"fdata" as following:
fdata <- cbind(matrix(unlist(filtered),ncol=28), myregime)
If I try names(filtered), it gives all the correct name for each vector, but
if I try names(fdata), it appears "filtered[[1]]" "filtered[[2]]" ...,
How can I keep the name in "fdata"?
2007 Oct 31
2
cbind()
Hello,
I would like to use the cbind() function to construct a matrix used in the
middle of a function as following
for (i in 1:1000) {
b[i] <- function(cbind(a[[1]][[i]],
a[[2]][[i]],a[[3]][[i]],...a[[67]][[i]]))
}
Is there an easy way of achieving this rather than "cbind" every column?
--
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2007 Nov 07
2
Linear Regression
Hello everyone,
I would like to a linear regression with the following code.
lm(a[,"fquamsci"]~., data=a)
a is a list with class "mts" "ts" , and "fquamsci" is the name of the
response variable in a. I would like to do a linear regression of "fquamsci"
to the rest of the variables. But it turns out the "fquamsci" is also
included in
2007 May 31
2
Import data from Access
Hi, I want to import some data from Access and I am using the following
codes:
testdb <- file.path("c/../db1")
channel <- odbcConnect("testdb")
sqlFetch(channel,"tbl",colnames = TRUE, rownames = FALSE)
It comes out the error message:
1: [RODBC] ERROR: state IM002, code 0, message [Microsoft][ODBC Driver
Manager] Data source name not found and no default
2007 Jun 01
2
tapply
Hello, I want to conduct normality test to a series of data and get the
p-value for each subset. I am using the following codes, but it does not
work.
tapply(re, list(reg, ast), pvalue(shapiro.test))
Could anyone give me some advice? Many thanks.
--
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2007 Jun 13
1
VGAM Pareto
I would like to fit a Pareto Distribution and I am using the following codes
fit=vglm(ycf1 ~ 1, pareto1(location=alpha), trace=TRUE, crit="c")
fitted(fit)
But the fitted values turn out to be the same for each observation. I guess
the problem is with "ycf1 ~ 1",
I would be grateful if anyone can give me some advice on how to define the
formula.
Many thanks
--
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2007 Jul 03
1
EWMA procedure to forecast variance
Hello,
I would like to use the Exponential Weighted Moving Average procedure to get
the variance. Is there any R function for doing this?
Many thanks.
--
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2007 Jul 24
1
Fit t distribution
Hi all, I am trying to fit t distribution using the function "tFit" in the
library(fBasics).
I am using the code tFit(datac[[2]]) and it returns the following list.
Title:
Student-t Parameter Estimation
Call:
tFit(x = datac[[2]])
Model:
Student-t Distribution
Estimated Parameter(s):
df
78.4428
I just wonder how can I refer to the estimated parameters. I tried
2007 Nov 13
2
cbind function
Hello everyone,
I would like to use the "cbind" function to construct a dataset, combining
some variable I defined before.
The codes are something like
var1 <- ...
var2 <- ...
var2 <- ...
...
data <- cbind(var1,var2,var3...)
The problem is I would like some flexibity in the data, i.e. the number of
the variables are not fixed. Is there a method of combine the uncertain
2007 Nov 30
1
No quote
Hello,
I define a dataframe named "Price" first and there are other dataframes as
well. Then I built an array named "code" containing all the dataframe name.
So If I call code[1], it is "Price".
Basicly, I would like to call the datafram with reference to the
array"code".e,g, If I want to call dataframe
"Prices", I use sth containing code[1]. It
2007 Dec 13
6
ls() pattern
Hello everyone,
I get some data in the following format and I would like to combine them to
form a dataframe.
The data is like:
cbcname1 = 0.1,
cbcname2= 0.2,
cbcname3=0.3,...
name1, name2, name2 are just some random names. I would like to achieve sth
like:
(cbcname1=0.1, cbcname2=0.2, cbcname3=0.3,......)
I am using the following codes
do.call(cbind,
2007 Sep 12
2
Tick intervals
Hi, I would like to plot a histogram with the following codes, and I would
like to make the tick intervals smaller. I tried to add "lab=c(1,1,12)", but
nothing changes.
par(mfrow=c(1,1),font=1, cex=0.8)
hist (data1, seq(-0.01,0.3,0.01),freq = FALSE,
main="Figure1.",xlab="return",lab=c(1,1,12))
lines(density(data1), col="blue")
Could anyone give me sone
2008 May 23
1
van der Corput sequences
In package fOptions, there are functions that generate
Halton sequences.
The van der Corput sequence for base 2 is a particular case
of the Halton sequence generated by:
n <- 8 # anything here...
x <- runif.halton(n, 1)
In fact, x <- runif.halton(n, dim) will generate the van der Corput
sequences for the base b as the i-th prime number in x[,i].
(in other words, if I want the van der