Displaying 20 results from an estimated 800 matches similar to: "alpha in Holt-Winters method"
2010 Jun 28
0
Seasonality - Centered MA vs. Holt-Winters
Hello,
I asked this question on the r-finance list server and didn't get a reply.
Thought I would try here to.
I am trying to deseasonalize some financial time series data and I wanted
some feedback on the best methods for doing this. I found two Centered
Moving Average and Holt-Winters. Which is better and/or more appropriate for
financial time series data in your opinion?
I understand
2009 Apr 15
2
Double seasonal holt winter using R
Dear Members,
I have been searching for a package in R which can handle multiple seasonality suggested by taylor(2003).
It will be great help if anybody has used this on R before (i.e. which package).
Thanks in Advance.
Best Regards
Atul Malik
[[alternative HTML version deleted]]
2006 Aug 30
2
how to read just a column
Hi,
how can I read, using for example read.table() or scan(), just one
column from a text file that has more columns without any header?
Thanks, bye.
1999 Dec 01
2
nlmin
I'm a very recent user of R. I have been adapting my Splus programmes
and I found only one (important) problem. There exists no function
"nlmin" in R and its substitute, "nlm", does not work well with my kind
of problems, sometimes no achieving convergence, other tines
"converging" to impossible values. My models are highly nonlinear and
are to be estimated by
2008 Apr 22
2
optimization and gradient
Dear all,
I am using the functions 'optim' and 'nlminb'. For both, you can provide
a function which computes the gradient of the objective function (to
enhance speed and precision). In my case, both the objective function
and the gradient take time to be computed and share many common
computations (similar matrix, products, etc...). Therefore, I have to
compute these
2007 May 08
2
statistics/correlation question NOT R question
This is not an R question but if anyone can help me, it's much
appreciated.
Suppose I have a series ( stationary ) y_t and a series x_t ( stationary
)and x_t has variance sigma^2_x and epsilon is normal
(0, sigma^2_epsilon )
and the two series have the relation
y_t = Beta*x_t + epsilon
My question is if there are particular values that sigma^2_x and
sigma^2_epsilon have to take in
1999 Jan 21
2
nlm question
Hello again
Is there any way (or an alternative non-linear minimiser) that arguments
to the function called in nlm can be passed in version 0.62.4? Like (I
believe) nlmin in a well known other program or optimise in R. Do we use
global variables? Shurely not!
\John
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r-help mailing list -- Read
2003 Sep 04
3
function is too long to keep source
Dear R users,
I am trying to minimise a function using "nlm".
I am getting the following error message: "Error: function is too long to
keep source"
The function is really very long (about 100 A4 pages).
Is there anything I could do to solve this problem?
At the moment I am using "nlmin" in S-Plus with no problems but I'd prefer
to use R.
Thank you very
2004 Jan 14
3
How can I test if time series residuals' are uncorrelated ?
Ok I made Jarque-Bera test to the residuals (merv.reg$residual)
library(tseries)
jarque.bera.test(merv.reg$residual)
X-squared = 1772.369, df = 2, p-value = < 2.2e-16
And I reject the null hypotesis (H0: merv.reg$residual are normally
distributed)
So I know that:
1 - merv.reg$residual aren't independently distributed (Box-Ljung test)
2 - merv.reg$residual aren't indentically
2008 Dec 22
2
AR(2) coefficient interpretation
I am a beginner in using R and I need help in the interpretation of AR result
by R. I used 12 observations for my AR(2) model and it turned out the
intercept showed 5.23 while first and second AR coefficients showed 0.40 and
0.46. It is because my raw data are in million so it seems the intercept is
too small and it doesn't make sense. Did i make any mistake in my code? My
code is as follows:
2005 Mar 05
4
How to use "lag"?
Is it possible to fit a lagged regression, "y[t]=b0+b1*x[t-1]+e",
using the function "lag"? If so, how? If not, of what use is the
function "lag"? I get the same answer from y~x as y~lag(x), whether
using lm or arima. I found it using y~c(NA, x[-length(x)])). Consider
the following:
> set.seed(1)
> x <- rep(c(rep(0, 4), 9), len=9)
> y <-
2003 Nov 17
2
Newbie question
I'm trying to find a good open source software to do sales forecasting using Holt Winters and Box Jenkins time series algorithm. Somebody pointed me that R is the best open source available for statistical computing. Are there functions to do Holt Winters and Box Jenkins time series prediction in R? If there is none, can some one point me a good GNU/freeware to do the sales forecasting using
2008 Sep 10
2
arima and xreg
Dear R-help-archive..
I am trying to figure out how to make arima prediction when I have a
process involving multivariate time series input, and one output time
series (output is to be predicted) .. (thus strictly speaking its an
ARMAX process). I know that the arima function of R was not designed
to handle multivariate analysis (there is dse but it doesnt handle
arma multivariate analysis, only
2012 Jul 28
4
quantreg Wald-Test
Dear all,
I know that my question is somewhat special but I tried several times to
solve the problems on my own but I am unfortunately not able to compute the
following test statistic using the quantreg package. Well, here we go, I
appreciate every little comment or help as I really do not know how to tell
R what I want it to do^^
My situation is as follows: I have a data set containing a
2007 May 21
1
Sample correlation coefficient question NOT R question
This is a statistics question not an R question. When calculating the
sample correlation coefficient cor(x_t,y_t) between say
two variables, x_t and y_t t=1,.....n ( one can assume that the
variables are in time but I don't think this really matters
for the question ), does someone know where I can find any piece of
literature that says that each (x_j,y_j) pair has
To be independent from the
2000 Apr 04
0
stochastic process transition probabilities estimation
Hi all,
I'm new with R (and S), and relatively new to statistics (I'm a
computer scientist), so I ask sorry in advance if my question is silly.
My problem is this: I have a (sample of a) discrete time stochastic
process {X_t} and I want to estimate
Pr{ X_t | X_{t-l_1}, X_{t-l_2}, ..., X_{t-l_k} }
where l_1, l_2, ..., l_k are some fixed time lags. It will be enough for
me to compute
2011 Dec 01
1
Estimation of AR(1) Model with Markov Switching
Dear R users,
I have been trying to obtain the MLE of the following model
state 0: y_t = 2 + 0.5 * y_{t-1} + e_t
state 1: y_t = 0.5 + 0.9 * y_{t-1} + e_t
where e_t ~ iidN(0,1)
transition probability between states is 0.2
I've generated some fake data and tried to estimate the parameters using the
constrOptim() function but I can't get sensible answers using it. I've tried
using
2002 Apr 09
2
Restricted Least Squares
Hi,
I need help regarding estimating a linear model where restrictions are imposed on the coefficients. An example is as follows:
Y_{t+2}=a1Y_{t+1} + a2 Y_t + b x_t + e_t
restriction
a1+ a2 =1
Is there a function or a package that can estimate the coefficient of a model like this? I want to estimate the coefficients rather than test them.
Thank you for your help
Ahmad Abu Hammour
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2009 Apr 20
1
Two or more dimensional root (Zero) finding
Good morning to all,
I should find the zero of a specific function with
respect to a vector of arguments.
Does it exist something similar in R?
Thank
you very much,
Enrico Foscolo
2009 Nov 02
1
AR Simulation with non-normal innovations - Correct
Dear Users,
I would like to simulate an AR(1) (y_t=ct1+y_t-1+e_t) model in R where the innovations are supposed to follow a t-GARCH(1,1) proccess.
By t-GARCH I want to mean that:
e_t=n_t*sqrt(h_t) and
h_t=ct2+a*(e_t)^2+b*h_t-1.
where n_t is a random variable with t-Student distribution.
If someone could give some guidelines, I can going developing the model.
I did it in matlab, but the loops