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  2. Algorithms for calculating variance - Wikipedia

    en.wikipedia.org/wiki/Algorithms_for_calculating...

    This algorithm can easily be adapted to compute the variance of a finite population: simply divide by n instead of n − 1 on the last line.. Because SumSq and (Sum×Sum)/n can be very similar numbers, cancellation can lead to the precision of the result to be much less than the inherent precision of the floating-point arithmetic used to perform the computation.

  3. Organoantimony chemistry - Wikipedia

    en.wikipedia.org/wiki/Organoantimony_chemistry

    Structure of (PhSb) 6 [5] Distibines are formally Sb II compounds, but feature tricoordinate Sb atoms with a single Sb-Sb bond. They may have interest as thermochromes.For example, tetramethyldistibine is colorless when gas, yellow when liquid, red when solid just below the melting point of 18.5 °C, shiny-blue when cooler, and again yellow at cryogenic temperatures.

  4. Mean value problem - Wikipedia

    en.wikipedia.org/wiki/Mean_value_problem

    In 1989, Tischler showed that the conjecture is true for the optimal bound = if has only real roots, or if all roots of have the same norm. [ 3 ] [ 4 ] In 2007, Conte et al. proved that K ≤ 4 d − 1 d + 1 {\displaystyle K\leq 4{\frac {d-1}{d+1}}} , [ 2 ] slightly improving on the bound K ≤ 4 {\displaystyle K\leq 4} for fixed d ...

  5. Squared deviations from the mean - Wikipedia

    en.wikipedia.org/wiki/Squared_deviations_from...

    Squared deviations from the mean (SDM) result from squaring deviations. In probability theory and statistics , the definition of variance is either the expected value of the SDM (when considering a theoretical distribution ) or its average value (for actual experimental data).

  6. Notation in probability and statistics - Wikipedia

    en.wikipedia.org/wiki/Notation_in_probability...

    Random variables are usually written in upper case Roman letters, such as or and so on. Random variables, in this context, usually refer to something in words, such as "the height of a subject" for a continuous variable, or "the number of cars in the school car park" for a discrete variable, or "the colour of the next bicycle" for a categorical variable.

  7. Multivariate Behrens–Fisher problem - Wikipedia

    en.wikipedia.org/wiki/Multivariate_Behrens...

    Let (,) (=, …,; =,) be independent random samples from two -variate normal distributions with unknown mean vectors and unknown dispersion matrices. The index i {\displaystyle i} refers to the first or second population, and the j {\displaystyle j} th observation from the i {\displaystyle i} th population is X i j {\displaystyle X_{ij}} .

  8. Antimony tetroxide - Wikipedia

    en.wikipedia.org/wiki/Antimony_tetroxide

    The material forms when Sb 2 O 3 is heated in air: [5] Sb 2 O 3 + 0.5 O 2Sb 2 O 4 ΔH = −187 kJ/mol. At 800 °C, antimony(V) oxide loses oxygen to give the same material: Sb 2 O 5 → Sb 2 O 4 + 0.5 O 2 ΔH = −64 kJ/mol. The material is mixed valence, containing both Sb(V) and Sb(III) centers.

  9. Mean value analysis - Wikipedia

    en.wikipedia.org/wiki/Mean_value_analysis

    To use the algorithm, we first compute the visit ratio row vector v, a vector such that v = v P. Now write L i ( n ) for the mean number of customers at queue i when there is a total of n customers in the system (this includes the job currently being served at queue i ) and W j ( n ) for the mean time spent by a customer in queue i when there ...