In chemistry, the mole fraction or molar fraction, also called mole proportion or molar proportion, is a quantity defined as the ratio between the amount of a constituent substance, ni, and the total amount of all constituents in a mixture, ntot :
Power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt, equal to one joule per second. Power is a scalar quantity.
Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 indicates more signal than noise.
The total harmonic distortion is a measurement of the harmonic distortion present in a signal and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. Distortion factor, a closely related term, is sometimes used as a synonym.
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit.
In economics, the GDP deflator is a measure of the money price of all new, domestically produced, final goods and services in an economy in a year relative to the real value of them. It can be used as a measure of the value of money. GDP stands for gross domestic product, the total monetary value of all final goods and services produced within the territory of a country over a particular period of time.
In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (Vout) that is a fraction of its input voltage (Vin). Voltage division is the result of distributing the input voltage among the components of the divider. A simple example of a voltage divider is two resistors connected in series, with the input voltage applied across the resistor pair and the output voltage emerging from the connection between them.
The dependency ratio is an age-population ratio of those typically not in the labor force and those typically in the labor force. It is used to measure the pressure on the productive population.
A receiver operating characteristic curve, or ROC curve, is a graphical plot that illustrates the performance of a binary classifier model at varying threshold values.
In economics, the debt-to-GDP ratio is the ratio between a country's government debt and its gross domestic product (GDP). A low debt-to-GDP ratio indicates that an economy produces goods and services sufficient to pay back debts without incurring further debt. Geopolitical and economic considerations – including interest rates, war, recessions, and other variables – influence the borrowing practices of a nation and the choice to incur further debt.
The Hoover index, also known as the Robin Hood index or the Schutz index, is a measure of income inequality. It is equal to the percentage of the total population's income that would have to be redistributed to make all the incomes equal.
The maximal total range is the maximum distance an aircraft can fly between takeoff and landing. Powered aircraft range is limited by the aviation fuel energy storage capacity considering both weight and volume limits. Unpowered aircraft range depends on factors such as cross-country speed and environmental conditions. The range can be seen as the cross-country ground speed multiplied by the maximum time in the air. The fuel time limit for powered aircraft is fixed by the available fuel and rate of consumption.
Poverty is measured in different ways by different bodies, both governmental and nongovernmental. Measurements can be absolute, which references a single standard, or relative, which is dependent on context. Poverty is widely understood to be multidimensional, comprising social, natural and economic factors situated within wider socio-political processes.
In pattern recognition, information retrieval, object detection and classification, precision and recall are performance metrics that apply to data retrieved from a collection, corpus or sample space.
In chemistry, the mass fraction of a substance within a mixture is the ratio of the mass of that substance to the total mass of the mixture. Expressed as a formula, the mass fraction is:
The mathematical principles of reinforcement (MPR) constitute of a set of mathematical equations set forth by Peter Killeen and his colleagues attempting to describe and predict the most fundamental aspects of behavior.
The risk-return ratio is a measure of return in terms of risk for a specific time period. The percentage return (R) for the time period is measured in a straightforward way:
In medical testing with binary classification, the diagnostic odds ratio (DOR) is a measure of the effectiveness of a diagnostic test. It is defined as the ratio of the odds of the test being positive if the subject has a disease relative to the odds of the test being positive if the subject does not have the disease.
Fiscal sustainability, or public finance sustainability, is the ability of a government to sustain its current spending, tax and other policies in the long run without threatening government solvency or defaulting on some of its liabilities or promised expenditures. There is no consensus among economists on a precise operational definition for fiscal sustainability, rather different studies use their own, often similar, definitions. However, the European Commission defines public finance sustainability as: the ability of a government to sustain its current spending, tax and other policies in the long run without threatening the government's solvency or without defaulting on some of the government's liabilities or promised expenditures. Many countries and research institutes have published reports which assess the sustainability of fiscal policies based on long-run projections of country's public finances. These assessments attempt to determine whether an adjustment to current fiscal policies that is required to reconcile projected revenues with projected expenditures. The size of the required adjustment is given with measures such as the Fiscal gap. In empirical works, weak and strong fiscal sustainability are distinguished. Differences are related to both econometric techniques used for examination and variables involved.
The poverty gap index is a measure of the degree of poverty in a country. It is defined as extent to which individuals on average fall below the poverty line, and expresses it as a percentage of the poverty line.
