parametrai

Parametrai (singular: parametras) is the Lithuanian term for parameter, a quantity that defines or characterizes a system, model, or function. In many fields, parameters are distinguished from variables: parameters describe the structure or conditions under which a model operates, while variables are quantities that can change or be observed. Parameters may be fixed constants, design choices, or quantities to be estimated from data.

In mathematics and modeling, a parameter is a value that determines the form or behavior of a function or equation. For a given set of parameter values, the model yields predictions; changing parameters changes the output without altering the underlying equation's form. Parameters can be symbolic or numerical and may depend on the context (e.g., time-dependent parameters).

In statistics, parameters refer to fixed, unknown quantities of a population, such as the mean or variance. They contrast with statistics, which are estimates derived from samples. Many methods—estimation, hypothesis testing, and Bayesian inference—seek to infer or update parameter values based on observed data.

In computing and engineering, parameters appear as input values to functions, procedures, or systems. They define interfaces (location, size, configuration) and can be mandatory or optional with default values. Parameterization is the process of expressing a system in terms of parameters, often to facilitate analysis, simulation, or optimization.

Applications of parameter analysis include calibration of models to observed data, sensitivity analysis to identify influential parameters, and optimization to find parameter sets that improve performance. Parameter identifiability concerns whether unique parameter values can be determined from data.

Historically, the concept derives from Latin and Greek terms meaning "things measured alongside" and is widely used across sciences. In Lithuanian usage, parametrai is common in technical writing, research, and documentation to refer to the quantities that define models and systems.