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  2. Numeric precision in Microsoft Excel - Wikipedia

    en.wikipedia.org/wiki/Numeric_precision_in...

    Excel maintains 15 figures in its numbers, but they are not always accurate; mathematically, the bottom line should be the same as the top line, in 'fp-math' the step '1 + 1/9000' leads to a rounding up as the first bit of the 14 bit tail '10111000110010' of the mantissa falling off the table when adding 1 is a '1', this up-rounding is not undone when subtracting the 1 again, since there is no ...

  3. Unbiased estimation of standard deviation - Wikipedia

    en.wikipedia.org/wiki/Unbiased_estimation_of...

    One way of seeing that this is a biased estimator of the standard deviation of the population is to start from the result that s 2 is an unbiased estimator for the variance σ 2 of the underlying population if that variance exists and the sample values are drawn independently with replacement. The square root is a nonlinear function, and only ...

  4. Standard deviation - Wikipedia

    en.wikipedia.org/wiki/Standard_deviation

    A little algebra shows that the distance between P and M (which is the same as the orthogonal distance between P and the line L) (¯) is equal to the standard deviation of the vector (x 1, x 2, x 3), multiplied by the square root of the number of dimensions of the vector (3 in this case).

  5. Tsiolkovsky rocket equation - Wikipedia

    en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

    A rocket's required mass ratio as a function of effective exhaust velocity ratio. The classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity and can thereby move due to the ...

  6. Elo rating system - Wikipedia

    en.wikipedia.org/wiki/Elo_rating_system

    In 2011 after analyzing 1.5 million FIDE rated games, Jeff Sonas demonstrated according to the Elo formula, two players having a rating difference of X actually have a true difference of around X(5/6). Likewise, one can leave the rating difference alone and divide by 480 instead of 400.

  7. Non-linear least squares - Wikipedia

    en.wikipedia.org/wiki/Non-linear_least_squares

    These equations form the basis for the Gauss–Newton algorithm for a non-linear least squares problem. Note the sign convention in the definition of the Jacobian matrix in terms of the derivatives. Formulas linear in J {\displaystyle J} may appear with factor of − 1 {\displaystyle -1} in other articles or the literature.

  8. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    The general form of its probability density function is [2] [3] = (). The parameter ⁠ μ {\displaystyle \mu } ⁠ is the mean or expectation of the distribution (and also its median and mode ), while the parameter σ 2 {\textstyle \sigma ^{2}} is the variance .

  9. Mass balance - Wikipedia

    en.wikipedia.org/wiki/Mass_balance

    where w C, w H, w S, w O refer to the mass fraction of each element in the fuel oil, sulfur burning to SO 2, and AFR mass refers to the air-fuel ratio in mass units. For 1 kg of fuel oil containing 86.1% C, 13.6% H, 0.2% O, and 0.1% S the stoichiometric mass of air is 14.56 kg, so AFR = 14.56. The combustion product mass is then 15.56 kg.