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  2. 68–95–99.7 rule - Wikipedia

    en.wikipedia.org/wiki/68–95–99.7_rule

    In statistics, the 68–95–99.7 rule, also known as the empirical rule, and sometimes abbreviated 3sr, is a shorthand used to remember the percentage of values that lie within an interval estimate in a normal distribution: approximately 68%, 95%, and 99.7% of the values lie within one, two, and three standard deviations of the mean, respectively.

  3. Per-unit system - Wikipedia

    en.wikipedia.org/wiki/Per-unit_system

    In the power systems analysis field of electrical engineering, a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. . Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to t

  4. Mass fraction (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Mass_fraction_(chemistry)

    Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called percentage by weight, abbreviated wt.% or % w/w; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size ; mole fraction (percentage by moles , mol%) and volume fraction ...

  5. Duty cycle - Wikipedia

    en.wikipedia.org/wiki/Duty_cycle

    Similarly, for pulse (10001000) the duty cycle will be 25% because the pulse remains high only for 1/4 of the period and remains low for 3/4 of the period. Electrical motors typically use less than a 100% duty cycle. For example, if a motor runs for one out of 100 seconds, or 1/100 of the time, then, its duty cycle is 1/100, or 1 percent. [10]

  6. Percentage solution - Wikipedia

    en.wikipedia.org/wiki/Percentage_solution

    Percentage solution may refer to: Mass fraction (or "% w/w" or "wt.%"), for percent mass; Volume fraction (or "% v/v" or "vol.%"), volume concentration, for percent volume "Mass/volume percentage" (or "% m/v") in biology, for mass per unit volume; incorrectly used to denote mass concentration (chemistry). See usage in biology

  7. Baker percentage - Wikipedia

    en.wikipedia.org/wiki/Baker_percentage

    The total or sum of the baker's percentages is called the formula percentage. The sum of the ingredient masses is called the formula mass (or formula "weight"). Here are some interesting calculations: The flour's mass times the formula percentage equals the formula mass: [11]

  8. Atomic ratio - Wikipedia

    en.wikipedia.org/wiki/Atomic_ratio

    The atomic ratio is a measure of the ratio of atoms of one kind (i) to another kind (j). A closely related concept is the atomic percent (or at.%), which gives the percentage of one kind of atom relative to the total number of atoms. [1]

  9. Attributable fraction for the population - Wikipedia

    en.wikipedia.org/wiki/Attributable_fraction_for...

    For example, in 1953 Levin's paper estimated that lung cancer has a relative risk of 3.6–13.4 in smokers compared to non-smokers, and that the proportion of the population exposed to smoking was 0.5–0.96, resulting in the high AF p value of 0.56–0.92. [6]