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  2. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    The simplest case of a normal distribution is known as the standard normal distribution or unit normal distribution. This is a special case when μ = 0 {\textstyle \mu =0} and σ 2 = 1 {\textstyle \sigma ^{2}=1} , and it is described by this probability density function (or density): φ ( z ) = e − z 2 2 2 π . {\displaystyle \varphi (z ...

  3. Equivalent concentration - Wikipedia

    en.wikipedia.org/wiki/Equivalent_concentration

    Since only 0.5 mol of H 2 SO 4 are needed to neutralize 1 mol of OH −, the equivalence factor is: If the concentration of a sulfuric acid solution is c (H 2 SO 4) = 1 mol/L, then its normality is 2 N. It can also be called a "2 normal" solution. Similarly, for a solution with c (H 3 PO 4) = 1 mol/L, the normality is 3 N because phosphoric ...

  4. Multivariate normal distribution - Wikipedia

    en.wikipedia.org/wiki/Multivariate_normal...

    The multivariate normal distribution is said to be "non-degenerate" when the symmetric covariance matrix is positive definite. In this case the distribution has density [5] where is a real k -dimensional column vector and is the determinant of , also known as the generalized variance.

  5. Mass concentration (chemistry) - Wikipedia

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

    In chemistry, the mass concentration ρi (or γi) is defined as the mass of a constituent mi divided by the volume of the mixture V. [1] For a pure chemical the mass concentration equals its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called the density of a component in a mixture.

  6. Fick's laws of diffusion - Wikipedia

    en.wikipedia.org/wiki/Fick's_laws_of_diffusion

    Under an idealized reaction condition for A + B → product in a diluted solution, Smoluchovski suggested that the molecular flux at the infinite time limit can be calculated from Fick's laws of diffusion yielding a fixed/stable concentration gradient from the target molecule, e.g. B is the target molecule holding fixed relatively, and A is the ...

  7. Cumulative distribution function - Wikipedia

    en.wikipedia.org/wiki/Cumulative_distribution...

    The cumulative distribution function of a real-valued random variable is the function given by [2]: p. 77. (Eq.1) where the right-hand side represents the probability that the random variable takes on a value less than or equal to . The probability that lies in the semi-closed interval , where , is therefore [2]: p. 84.

  8. Area density - Wikipedia

    en.wikipedia.org/wiki/Area_density

    The area density (also known as areal density, surface density, superficial density, areic density, mass thickness, column density, or density thickness) of a two-dimensional object is calculated as the mass per unit area. The SI derived unit is the " kilogram per square metre " (kg·m −2). In the paper and fabric industries, it is called ...

  9. Log-normal distribution - Wikipedia

    en.wikipedia.org/wiki/Log-normal_distribution

    Then, the distribution of the random variable. is called the log-normal distribution with parameters and . These are the expected value (or mean) and standard deviation of the variable's natural logarithm, not the expectation and standard deviation of itself. Relation between normal and log-normal distribution.