Questions tagged [arima]

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1 answer
155 views

Why is $Z_t$ uncorrelated with $X_{t-1}$ in $X_t=\theta X_{t-1}+Z_t$?

In a solution to the problem below, the teaching assistant solves it by calculating $\mathbb{E}[X_t^2]$ and ends up with also having to calculate $\mathbb{E}[X_{t-1}Z_t]$ after expanding the square. ...
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0 votes
0 answers
183 views

Do I use % return, log return or diff of prices to plot ACF?

I am reading a book on time series. To make a non-stationary series stationary, sometimes we need to difference the series. When it comes to finance, prices are non-stationary. Many authors fit ARMA ...
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0 votes
1 answer
214 views

How are the values of the ARMA process linked in python

In the code below, you can see that 'ret' is an ARMA process, and I am trying to see how the ret[0], etc... ret3, ret4, etc. are linked to each other, and although I know the formula for the ARMA ...
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1 vote
0 answers
49 views

Price Prediction Intervals from Forecasted Returns (ARIMA)

I have successfully fit an ARIMA model to a time series of the daily returns of power futures prices. The question I have is: How can I create a prediction interval for the prices? Or, alternatively, ...
0 votes
0 answers
53 views

What is the Id in the ARIMA model in Notes on financial risk of Privault?

I hope this is the right place to ask this question. I am studying the time series from Privault's Notes on Financial Risks. In the ARIMA model part I can't understand what is "I_d", it is ...
2 votes
0 answers
72 views

Electricity Futures Risk Premiums With ARIMA

I am attempting to model long-term electricity prices using today's futures prices. Unlike most futures, electricity is delivered over a period of time (usually a month), rather than at a point in ...
0 votes
0 answers
34 views

ARMAX model with rolling window for predicting inflation

First of all, similar questions like mine are answered on this forum but I never quite saw an answer to this specific question. I'm trying to predict inflation by using an AR model with exogenous ...
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1 vote
1 answer
97 views

Modelling Skew when using ARMA Time Series

I am currently modelling financial time series via ARMA processes, but I have reason to believe that in addition to significant autocorrelation, the time series also exhibit skewness. Is there a way ...
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-2 votes
1 answer
81 views

Should stock return series be modeled with a parametric distribution, or an autoregressive function? [closed]

If I have prior knowledg that a stock return series follows a parametric distribution, such as a Student t-distribution with 4 degrees of freedom, without actively looking for prior knowledge of ...
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5 votes
0 answers
220 views

How to model financial HFT time-series data with multi scale autocorrelation

I work with tick level time-series univariate prices data. Tick level means that there are hundreds to thousands observations per second. The observations are timestamped, so one can use both wall ...
1 vote
0 answers
73 views

Exploding forecast when increasing sample size in ARIMA in R/Python

I am fitting ARFIMA - eGARCH to time-series log returns in Python using R Rugarch package. The sample size is 2000, and I am doing 1-step ahead forecast. The following is the output ...
0 votes
0 answers
115 views

Inter-temporal structural stability of stock markets

For my bachelor thesis I am trying to determine structural stability of some stock market in the following way: Identify an ARMA model for the whole sample Split the sample in two parts, and estimate ...
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0 votes
0 answers
52 views

Fitting a Spread into ARIMA AR(1) process

I'm a newbie to econometrics. I've simply ran a regression and have coefficient values of the variables. I'm running a regression for a crypto data, and I've gotten the Spread of the variables. To ...
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1 vote
2 answers
157 views

Exchange rate trend-stationarity

I am kinda new to time-series analysis, I want model CEE (EUR/HUF, EUR/PLN, EUR/CZK, EUR/CHF) exchange rates with ARIMA. I understand that according to Box-Jenkins modeling, I should first check if my ...
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1 vote
0 answers
155 views

Conditional and unconditional variance, autocovariance and autocorrelation of an ARMA process

Given an ARMA(1,1) process $x_t = a + bx_{t-1} + \varepsilon_t + \theta\varepsilon_{t-1}$, how can we find the conditional variance, i.e. $Var_{t-1}(x_t)$, find the unconditional variance, i.e. $Var(...
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0 votes
0 answers
97 views

Is non-linear correlation problematic in financial time series prediction?

Many traditional finance models assume linear relationships between variables and features. Aren't linear correlations/covariances unable to capture financial processes empirically since they actually ...
  • 2,865
1 vote
1 answer
221 views

What are some good models for stock price predictions?

For the fitting and forecasting of time-series data on stock price, the most frequent model I have heard of is ARIMA. ARIMA is actually conducting a regression of stock prices and residuals of stock ...
2 votes
0 answers
47 views

The residuals of GARCH model reject Engle’s Test despite large parameters

I'm trying to build a model to predict the volatility for a financial asset with ARIMA-GARCH model. (I use log returns as data) I fit my ARIMA model with AIC and I did Engle’s Test to ensure there is ...
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0 votes
1 answer
388 views

Can ARMA and GARCH models be estimated separately in ARMA/GARCH?

Can I use the residuals of the ARMA model to build a GARCH model(with Zero mean)? If so, does this mean that this GARCH model(with Zero mean) has no effect on ARMA's estimates. For example, if I want ...
0 votes
0 answers
126 views

Fitting a non-stationary GARCH model

I'm very new to financial time series. I have a dataset containing the daily simple returns of the Dow Jones Industrial Average and I want to model a (univariate) GARCH model for the daily logreturns. ...
3 votes
0 answers
102 views

Expected Shortfall for ARMA-GARCH Model

I need to find an analytical solution for the 99% confidence expected shortfall (CVaR) for a long position of 100 dollars at time $t$ for an asset with returns modeled by an ARMA(1,1)-GARCH(1,1) model ...
8 votes
2 answers
2k views

Differencing vs Detrending financial time series

I'm quite newbie to time series analysis and I have to understand what's the difference between differencing time series (i.e considering $Y_t= X_t-X_{t-1}$) and detrending (using linear regression ...
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2 votes
1 answer
63 views

ARMA moments proof

Consider a standard ARMA(1,1) process such as $$x_t - \beta x_{t-1} = \theta u_{t-1} + u_t$$ where $u_t$ is i.i.d. $u_t \sim N(0,\sigma^2)$. I know how to derive mean and variance with stationary ...
1 vote
0 answers
439 views

Combining SARIMA and GARCH model for prediction in python

I need to understand the concept of combining (S)ARIMA and (G)ARCH model for the predicting time-series data. I understand that after fitting the arima model ...
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3 votes
2 answers
229 views

Confidence Intervals for ARMA+GARCH forecasts

I have fitted an ARMA(1,1)+GARCH(1,1) model to my logreturns series. When it comes to my standarized error's distribution however, I have opted for a Skewed Generalized Error Distribution, because of ...
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2 votes
0 answers
130 views

Problem with Hurst exponent estimation for ARFIMA models

guys. I try to realize my ARFIMA model identification script in R. I try to find the best method for unbiased Hurst exponent estimation (fractional difference parameter could be found as Hurst - 0.5) ...
  • 221
0 votes
1 answer
4k views

MLE error in R: initial value in 'vmmin' is not finite

I am trying to fit an ARIMA(1,1)-GARCH(1,1) model. I changed the starting values a lot but still its returning the same error. Below is my code which contains two functions ...
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1 vote
0 answers
78 views

What kind of ARMA-GARCH model is that?

My question is what kind of ARMA-GARCH model is the following equation and how to specify it in rugarch R module: $$r_{t+1}- r_t = \alpha_0 + \alpha_1r_t+\...
1 vote
2 answers
318 views

Error distribution assumption in a simple ARIMA model

why in an ARIMA-GARCH structure I have to assume an error distribution to run the estimation while in a simple ARIMA model it is not required? Thank you
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1 vote
1 answer
61 views

Can GARCH volatility simulations generally be applied to return-modelling models?

This may be a naive question, but I still hope some discussion can elucidate a (so far) totally nebulous point for me. I've recently learned that GARCH models can give one simulations of ...
-1 votes
1 answer
82 views

ARIMA vs ARIMA + GARCH [closed]

If an ARIMA model converges quickly, would using GARCH improve the forecast performance? By improve I mean provide longer time periods for forecasts. Basically trying to forecast returns.
  • 11
0 votes
0 answers
796 views

Interpreting ACF/PACF of return series

Researching a return series on some currency pairs I grabbed 2 years worth of daily data and got to work trying to fit an ARIMA/GARCH model to it. Fitting the (log) return series: ...
user avatar
1 vote
0 answers
213 views

ARMA-GARCH Forecasting [closed]

I want to forecast a differenced time series of an Index using the combined ARMA-GARCH model (because I want to forecast the mean and not the variance). My model is a ARMA(2,2)-GARCH(1,1) model. So ...
1 vote
1 answer
94 views

Are some stock prices not ARIMA(0,1,0) processes?

I am studying stock prices. Let Pt be price of stock at time t. While Pt is non stationary, the return, rt=log(Pt/Pt-1) is stationary. However, when I study on rt, I decide on an ARMA(0,1) without ...
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1 vote
1 answer
549 views

Joint estimation of GARCH models with ARMA terms in the conditional mean: a necessity?

Supposing I am using the following models to forecast conditional volatility of index returns, whereby In-sample data is 1996-2007 and out of sample data is 2007-2012, using GARCH type models. I have ...
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2 votes
0 answers
447 views

VARMA GARCH modelling in R

I want to simulate a VARMA-GARCH process in R. Unfortunately, I found no package to help me with that. I tried modelling the MGARCH part on itw own and combine it with the VARMA simulation using MTS ...
3 votes
1 answer
692 views

Modeling tail data using Generalized Pareto distribution

I just estimated a ARMA(1,1)+GARCH(1,1)+Threshold order(1) equation for time series of stock prices. Now I'm going to estimate the residuals' marginal ...
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2 votes
4 answers
425 views

ARIMA model coefficients from discontinuous data series

Stock prices are not stationary processes during all week or all day. For example EURGBP has low variability at night in Europe but during working hours is changing much more dynamic because of market ...
3 votes
1 answer
2k views

Please advice free Java library for classical time series forecasting

I've got an ARIMA model (with a GARCH model for variance estimation) and parameters estimated in Matlab for my set of data. Now I need to use this model in my Java based application for making ...
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1 vote
0 answers
146 views

ARIMA prediction for currencies

I was browsing TradingEconomics.com and I came across their forecast models which immediately captivated my interest. They describe them as "projected using an autoregressive integrated moving average ...
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1 vote
0 answers
135 views

x13 Arima analysis with negative values

I'm running x13 Arima analysis on a US GDP series to get the "trend" component. ...
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2 votes
0 answers
137 views

Estimating time-varying tail dependence for Archimedean copulas

Patton (2006) defines the upper tail dependence coefficient for a time-varying bivariate SJC copula as $$\tau^u_t=\Lambda \left(\omega_u + \beta_u \tau^u_{t-1}+\alpha_u \frac{1}{10}\sum^{10}_{i=1}|u_{...
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3 votes
1 answer
1k views

Python regenerating ARMA params using statsmodels

I am trying to regenerate the ARMA parameters from statsmodel in python. The code I am using is: ...
0 votes
1 answer
197 views

Python statsmodel ARMA question

I am reading through the documentation of statsmodel package in python from the link The (p,q) order of the model for the number of AR parameters, differences, and MA parameters to use. How do I ...
38 votes
5 answers
7k views

Why aren't econometric models used more in Quant Finance?

There is a big body of literature on econometric models like ARIMA, ARIMAX or VAR. Yet to the best of my knowledge practically nobody is making use of that in Quantitative Finance. Yes, there is a ...
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2 votes
1 answer
274 views

Automate selection of BIC-minimizing ARIMA(1,0,X) model

I want to estimate an ARIMA(1,0,X) model. The MA(X) in the model is selected to minimize BIC. I have the following code employing the function auto.arima from "...
1 vote
0 answers
63 views

Distribution of AR and MA polynoms roots in ARMA/ARMA-GARCH models

I have another noob question. So, for example, I have ARMA(2,2) model: $$ x_{t} = \phi_{1}x_{t-1} + \phi_{2}x_{t-2} + e_{t} + \theta_{1} e_{t-1} + \theta_{2} e_{t-2}$$. So, I have 2 polynoms: $$1 - \...
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2 votes
1 answer
300 views

distribution of AR, MA coefficients estimation in ARMA-GARCH models

could anyone give me an information about distributions of AR and MA coefficients via estimation? So, for example, I have ARMA(1,1)-GARCH(1,1) model with the same AR(1) and MA(1) parameters ...
  • 221
1 vote
1 answer
931 views

One-step ahead forecast of a AR(1) process (GARCH context)

I am using a Matlab toolbox for obtaining one-step ahead forecasts of the conditional mean from the ARMA(1,0)-GARCH(1,1) process and I have encountered a piece of code that contains, in my opinion, a ...
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3 votes
1 answer
479 views

Is that a good way to work with the ARMA model?

I would like to share with you what I am doing to get your point of view, and to make a better trading system in collaboration. I am working on EURUSD forex, and I am trying to find a way to place ...