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Latent Growth Modeling
Latent growth modeling is a statistical technique used in the structural equation modeling (SEM) framework to estimate growth trajectories. It is a longitudinal analysis technique to estimate growth over a period of time. It is widely used in the social sciences, including psychology and education. It is also called latent growth curve analysis. The latent growth model was derived from theories of SEM. General purpose SEM software, such as OpenMx, lavaan (both open source packages based in R), AMOS, Mplus, LISREL, or EQS among others may be used to estimate growth trajectories. Background Latent Growth Models represent repeated measures of dependent variables as a function of time and other measures. Such longitudinal data share the features that the same subjects are observed repeatedly over time, and on the same tests (or parallel versions), and at known times. In latent growth modeling, the relative standing of an individual at each time is modeled as a function of an unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Equation Modeling
Structural equation modeling (SEM) is a diverse set of methods used by scientists for both observational and experimental research. SEM is used mostly in the social and behavioral science fields, but it is also used in epidemiology, business, and other fields. A common definition of SEM is, "...a class of methodologies that seeks to represent hypotheses about the means, variances, and covariances of observed data in terms of a smaller number of 'structural' parameters defined by a hypothesized underlying conceptual or theoretical model,". SEM involves a model representing how various aspects of some phenomenon are thought to causally connect to one another. Structural equation models often contain postulated causal connections among some latent variables (variables thought to exist but which can't be directly observed). Additional causal connections link those latent variables to observed variables whose values appear in a data set. The causal connections are represented using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Curve (statistics)
The growth curve model in statistics is a specific multivariate linear model, also known as GMANOVA (Generalized Multivariate Analysis-Of-Variance). It generalizes MANOVA by allowing post-matrices, as seen in the definition. Definition Growth curve model: Let X be a ''p''×''n'' random matrix corresponding to the observations, A a ''p''×''q'' within design matrix with ''q'' ≤ ''p'', B a ''q''×''k'' parameter matrix, C a ''k''×''n'' between individual design matrix with rank(''C'') + ''p'' ≤ ''n'' and let Σ be a positive-definite ''p''×''p'' matrix. Then : X=ABC+\Sigma^E defines the growth curve model, where A and C are known, B and Σ are unknown, and E is a random matrix distributed as ''N''''p'',''n''(0,''I''''p'',''n''). This differs from standard MANOVA by the addition of C, a "postmatrix". History Many writers have considered the growth curve analysis, among them Wishart (1938), Box (1950) and Rao (1958). Potthoff and Roy in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenMx
OpenMx is an open source program for extended structural equation modeling. It runs as a package under R. Cross platform, it runs under Linux, Mac OS and Windows.S. Boker, M. Neale, H. Maes, M. Wilde, M. Spiegel, T. Brick, J. Spies, R. Estabrook, S. Kenny, T. Bates, P. Mehta and J. Fox. (2011). OpenMx: An Open Source Extended Structural Equation Modeling Framework. ''Psychometrika'', 76/ref> Overview OpenMx consists of an R library of functions and optimizers supporting the rapid and flexible implementation and estimation of Structural equation modeling, SEM models. Models can be estimated based on either raw data (with FIML modelling) or on correlation or covariance matrices. Models can handle mixtures of continuous and ordinal data. The current version is OpenMx 2, and is available on CRAN. Path analysis, Confirmatory factor analysis, Latent growth modeling, Mediation analysis are all implemented. Multiple group models are implemented readily. When a model is run, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
R (programming Language)
R is a programming language for statistical computing and Data and information visualization, data visualization. It has been widely adopted in the fields of data mining, bioinformatics, data analysis, and data science. The core R language is extended by a large number of R package, software packages, which contain Reusability, reusable code, documentation, and sample data. Some of the most popular R packages are in the tidyverse collection, which enhances functionality for visualizing, transforming, and modelling data, as well as improves the ease of programming (according to the authors and users). R is free and open-source software distributed under the GNU General Public License. The language is implemented primarily in C (programming language), C, Fortran, and Self-hosting (compilers), R itself. Preprocessor, Precompiled executables are available for the major operating systems (including Linux, MacOS, and Microsoft Windows). Its core is an interpreted language with a na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AMOS (statistical Software Package)
AMOS or Advanced Mortar System is a Finno-Swedish 120 mm semi-automatic twin Barrel (firearms), barrelled, Breech-loading weapon, breech loaded Mortar (weapon), mortar Gun turret, turret. AMOS has been fitted to a wide range of armoured vehicles, such as the Sisu Pasi, Patria AMV and Combat Vehicle 90. The Swedish Navy originally planned to fit AMOS to the CB90 assault craft, but found that it was too small to carry it. Instead, a project to develop the larger Combat Boat 2010 was launched specifically to carry AMOS. Sweden cancelled its acquisition of the AMOS in 2009 due to budget regulations by recommendations from Genomförandegruppen. In 2016 a new self propelled mortar system called ''Mjölner'' based on a CV90 hull was ordered by the Swedish armed forces, it is based on the AMOS and has many visual similarities but is not as advanced. Design When fitted to a vehicle, both GPS- and Inertial navigation system, inertia positioning are used. The electronic fire-contro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LISREL
LISREL (linear structural relations) is a proprietary statistical software package used in structural equation modeling (SEM) for manifest and latent variables. History LISREL was developed in the 1970s by Karl Jöreskog, then a scientist at Educational Testing Service in Princeton, New Jersey, and Dag Sörbom, later both professors of Uppsala University in Sweden. Command language, graphical user interface and delivery LISREL is mainly syntax-based, although recent versions have featured a graphical user interface (GUI). SSI (Scientific Software International) has recently changed from e-Academy to a "home-built" solution for distributing the rental (6- or 12-month) versions of their software. See also * Confirmatory factor analysis * Multivariate analysis * Path analysis (statistics) * Structural equation modeling Structural equation modeling (SEM) is a diverse set of methods used by scientists for both observational and experimental research. SEM is used mostly in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EQS (software)
EQS may refer to: * Etixx-Quick-Step, a professional cycling team * Mercedes-Benz EQS, an electric sedan * Mercedes-Benz EQS SUV, an electric sport utility vehicle * Environmental Quality Standard, an environmental standard for environmental quality Environmental quality is considered by scientists and environmentalists as the properties and attributes of the environment, generalized or on a small scale, as they affect human beings and other organisms. It is a measure of the condition of an e ... * Esquel Airport (IATA airport code: EQS), Esquel, Chubut Province, Argentina See also * EQ (other) * {{dab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generalised Logistic Function
The generalized logistic function or curve is an extension of the logistic function, logistic or sigmoid function, sigmoid functions. Originally developed for growth modelling, it allows for more flexible S-shaped curves. The function is sometimes named Richards's curve after Francis John Richards, F.J.Richards, who proposed the general form for the family of models in 1959. Definition Richards's curve has the following form: :Y(t) = A + where Y = weight, height, size etc., and t = time. It has six parameters: *A: the left horizontal asymptote; *K: the right horizontal asymptote when C=1. If A=0 and C=1 then K is called the carrying capacity; *B: the growth rate; *\nu > 0 : affects near which asymptote maximum growth occurs. *Q: is related to the value Y(0) *C: typically takes a value of 1. Otherwise, the upper asymptote is A + The equation can also be written: :Y(t) = A + where M can be thought of as a starting time, at which Y(M) = A + . Including both Q and M can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logistic Function
A logistic function or logistic curve is a common S-shaped curve ( sigmoid curve) with the equation f(x) = \frac where The logistic function has domain the real numbers, the limit as x \to -\infty is 0, and the limit as x \to +\infty is L. The exponential function with negated argument (e^ ) is used to define the standard logistic function, depicted at right, where L=1, k=1, x_0=0, which has the equation f(x) = \frac and is sometimes simply called the sigmoid. It is also sometimes called the expit, being the inverse function of the logit. The logistic function finds applications in a range of fields, including biology (especially ecology), biomathematics, chemistry, demography, economics, geoscience, mathematical psychology, probability, sociology, political science, linguistics, statistics, and artificial neural networks. There are various generalizations, depending on the field. History The logistic function was introduced in a series of three papers by Pier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exponential Growth
Exponential growth occurs when a quantity grows as an exponential function of time. The quantity grows at a rate directly proportional to its present size. For example, when it is 3 times as big as it is now, it will be growing 3 times as fast as it is now. In more technical language, its instantaneous rate of change (that is, the derivative) of a quantity with respect to an independent variable is proportional to the quantity itself. Often the independent variable is time. Described as a function, a quantity undergoing exponential growth is an exponential function of time, that is, the variable representing time is the exponent (in contrast to other types of growth, such as quadratic growth). Exponential growth is the inverse of logarithmic growth. Not all cases of growth at an always increasing rate are instances of exponential growth. For example the function f(x) = x^3 grows at an ever increasing rate, but is much slower than growing exponentially. For example, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gompertz Function
The Gompertz curve or Gompertz function is a type of mathematical model for a time series, named after Benjamin Gompertz (1779–1865). It is a sigmoid function which describes growth as being slowest at the start and end of a given time period. The right-side or future value asymptote of the function is approached much more gradually by the curve than the left-side or lower valued asymptote. This is in contrast to the simple logistic function in which both asymptotes are approached by the curve symmetrically. It is a special case of the generalised logistic function. The function was originally designed to describe human mortality, but since has been modified to be applied in biology, with regard to detailing populations. History Benjamin Gompertz (1779–1865) was an actuary in London who was privately educated. He was elected a fellow of the Royal Society in 1819. The function was first presented in his June 16, 1825 paper at the bottom of page 518. The Gompertz functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
