Parameter

{
  "id": "MLC-T-ENV-020202",
  "term": "Parameter",
  "field": "Environment",
  "definition": "1. Constants applied to a model that are obtained by theoretical calculation or measurements taken at another time and/or place, and are assumed to be appropriate for the place and time being studied.\n\n2. A number that describes a population.\n\n3. A quantity, usually unknown, such as a mean or a standard deviation characterizing a population. Commonly misused for \"variable,\" \"characteristic,\" or \"property.\"\n\n4. The substance or property being measured. The parameter is replaced by the concept of a Characteristic in new STORET. The entire list of parameters can be downloaded from the Reference Tables Page (http://www.epa.gov/storpubl/legacy/ref_tables.htm).\n\n5. A variable, measurable property whose value is a determinant of the characteristics of a system; e.g. temperature, pressure, and density are parameters of the atmosphere.\n\n6. A setting that controls how a control strategy is run, such as the selection of the target pollutant or the cost year. The term parameter is also used in the context of cost equations. In that context, it means one of the numeric values used as an input to the cost equation.\n\n7. \"Any quantity such as a mean or a standard deviation characterizing a population. Commonly misused for 'variable,' 'characteristic,' or 'property' (QAMS 1993, 15).\n\n8. A value used to numerically describe a population of values, e.g., the mean and standard deviation; or a value used to describe a dose-response curve, e.g., the intercept and the slope of a linear dose-response.\n\n9. A value that characterizes the probability distribution of a random variable. (It is important to distinguish between this definition, and a second popular use of the term parameter when referring to an input variable in a mathematical equation or model.)\n\n10. A quantity used to calibrate or specify a model, such as parameters of a probability model (e.g., mean and standard deviation for a normal distribution). Parameter values are often selected by fitting a model to a calibration data set. (FAO/WHO 2003b)\n\n11. A parameter is a value, usually unknown (and which therefore has to be estimated), used to represent a certain population characteristic. For example, the population mean is a parameter that is often used to indicate the average value of a quantity. Within a population, a parameter is a fixed value which does not vary. Each sample drawn from the population has its own value of any statistic that is used to estimate this parameter. For example, the mean of the data in a sample is used to give information about the overall mean in the population from which that sample was drawn. Parameters are often assigned Greek letters (e.g., σ), whereas statistics are assigned Roman letters (e.g., s). (STEPS 1997)\n\n12. Parameters at 40 CFR 136.2 in Table 1B, which also cites the approved methods of analysis.\n\n13. Value used to numerically describe a population of values, e.g., the mean and standard deviation; or a value used to describe a dose-response curve, e.g., the intercept and the slope of a linear dose-response.\n\n14. The name of the characteristic being monitored and assessed.",
  "subject": "Information management and systems",
  "references": [
    "Waste and Cleanup Risk Assessment Glossary",
    "Program Evaluation Glossary",
    "Guidance for Quality Assurance Project Plans",
    "STORET Legacy Data Center Glossary",
    "Terms of Environment",
    "Control Strategy Tool (CoST) Glossary",
    "Environmental Modeling and Assessment Program (EMAP) Master Glossary; EMAP Master Glossary",
    "Benchmark Dose Software (BMDS) Glossary of Terms",
    "EPA Definitions of Terms Relevant to PRA and References for Further Reading at http://www.epa.gov/oswer/riskassessment/rags3adt/pdf/appendixe.pdf",
    "EPA Thesaurus of Terms Used in Microbial Risk Assessment: 5.9 Modeling, Statistics, and Math Terms at http://water.epa.gov/scitech/swguidance/standards/criteria/health/microbial/T59.cfm",
    "40 CFR 444.11 (CFR 2013)",
    "Expert Query Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/parameter/"
}