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Relative change. In any quantitative science, the terms relative change and relative difference are used to compare two quantities while taking into account the "sizes" of the things being compared, i.e. dividing by a standard or reference or starting value. [1] The comparison is expressed as a ratio and is a unitless number.
Fold change. Fold change is a measure describing how much a quantity changes between an original and a subsequent measurement. It is defined as the ratio between the two quantities; for quantities A and B the fold change of B with respect to A is B / A. In other words, a change from 30 to 60 is defined as a fold-change of 2.
Relative risk is used in the statistical analysis of the data of ecological, cohort, medical and intervention studies, to estimate the strength of the association between exposures (treatments or risk factors) and outcomes. [2] Mathematically, it is the incidence rate of the outcome in the exposed group, , divided by the rate of the unexposed ...
Decibel. The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel ( B ). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 1/10 (approximately 1.26) or root-power ratio of 10 1/20 (approximately 1.12 ).
The (classical) relative change above is but one of the possible measures/indicators of relative change or difference. An indicator of relative change from x (initial or reference value) to y (new value) (,) is a binary real-valued function defined for the domain of interest which satisfies the following properties:
describes the relationship between x, y and h, for a right triangle. Differentiating both sides of this equation with respect to time, t, yields. Step 3: When solved for the wanted rate of change, dy / dt, gives us. Step 4 & 5: Using the variables from step 1 gives us: Solving for y using the Pythagorean Theorem gives:
Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum. Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has vacuum as its dielectric. Relative permittivity is also commonly known ...
Temperature coefficient. A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property R that changes when the temperature changes by dT, the temperature coefficient α is defined by the following equation: Here α has the dimension of an inverse temperature ...