Search results
Results From The WOW.Com Content Network
Time series: random data plus trend, with best-fit line and different applied filters. In mathematics, a time series is a series of data points indexed (or listed or graphed) in time order. Most commonly, a time series is a sequence taken at successive equally spaced points in time.
According to Wold's decomposition theorem, [4] [5] [6] the ARMA model is sufficient to describe a regular (a.k.a. purely nondeterministic [6]) wide-sense stationary time series, so we are motivated to make such a non-stationary time series stationary, e.g., by using differencing, before we can use ARMA.
These data are well known as the Box and Jenkins gas furnace data for benchmarking predictive models. Commandeur & Koopman (2007, §10.4) [2] argue that the Box–Jenkins approach is fundamentally problematic. The problem arises because in "the economic and social fields, real series are never stationary however much differencing is done".
A seasonal pattern exists when a time series is influenced by seasonal factors. Seasonality occurs over a fixed and known period (e.g., the quarter of the year, the month, or day of the week). [1], the irregular component (or "noise") at time t, which describes random, irregular influences. It represents the residuals or remainder of the time ...
The CRAN task view on Time Series contains links to most of these. Mathematica has a complete library of time series functions including ARMA. [11] MATLAB includes functions such as arma, ar and arx to estimate autoregressive, exogenous autoregressive and ARMAX models. See System Identification Toolbox and Econometrics Toolbox for details.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
In time series analysis, the moving-average model (MA model), also known as moving-average process, is a common approach for modeling univariate time series. [ 1 ] [ 2 ] The moving-average model specifies that the output variable is cross-correlated with a non-identical to itself random-variable.
Today's best savings rates: Multiply your money at 10x the national average (up to 4.50% APY) AOL Don't get burned: 5 red flags to watch out for before choosing a financial advisor