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  2. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    In order to calculate the average and standard deviation from aggregate data, it is necessary to have available for each group: the total of values (Σx i = SUM(x)), the number of values (N=COUNT(x)) and the total of squares of the values (Σx i 2 =SUM(x 2)) of each groups.

  3. Numeric precision in Microsoft Excel - Wikipedia

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

    The last two examples illustrate what happens if x is a rather small number. In the second from last example, x = 1.110111⋯111 × 2 −50 ; 15 bits altogether. The binary is replaced very crudely by a single power of 2 (in this example, 2 −49 ) and its decimal equivalent is used.

  4. Summation - Wikipedia

    en.wikipedia.org/wiki/Summation

    In mathematics, summation is the addition of a sequence of numbers, called addends or summands; the result is their sum or total.Beside numbers, other types of values can be summed as well: functions, vectors, matrices, polynomials and, in general, elements of any type of mathematical objects on which an operation denoted "+" is defined.

  5. Microsoft Excel - Wikipedia

    en.wikipedia.org/wiki/Microsoft_Excel

    In the second line, the number one is added to the fraction, and again Excel displays only 15 figures. In the third line, one is subtracted from the sum using Excel. Because the sum in the second line has only eleven 1's after the decimal, the difference when 1 is subtracted from this displayed value is three 0's followed by a string of eleven 1's.

  6. Pairwise summation - Wikipedia

    en.wikipedia.org/wiki/Pairwise_summation

    For example, if the summands x i are uncorrelated random numbers with zero mean, the sum is a random walk and the condition number will grow proportional to . On the other hand, for random inputs with nonzero mean the condition number asymptotes to a finite constant as n → ∞ {\displaystyle n\to \infty } .

  7. Kahan summation algorithm - Wikipedia

    en.wikipedia.org/wiki/Kahan_summation_algorithm

    sum = t // Next time around, the lost low part will be added to y in a fresh attempt. next i return sum This algorithm can also be rewritten to use the Fast2Sum algorithm: [7] function KahanSum2(input) // Prepare the accumulator. var sum = 0.0 // A running compensation for lost low-order bits.

  8. Sum - Wikipedia

    en.wikipedia.org/wiki/Sum

    Sum (category theory), the generic concept of summation in mathematics; Sum, the result of summation, the addition of a sequence of numbers; 3SUM, a term from computational complexity theory; Band sum, a way of connecting mathematical knots; Connected sum, a way of gluing manifolds; Digit sum, in number theory; Direct sum, a combination of ...

  9. Prefix sum - Wikipedia

    en.wikipedia.org/wiki/Prefix_sum

    Express each term of the final sequence y 0, y 1, y 2, ... as the sum of up to two terms of these intermediate sequences: y 0 = x 0, y 1 = z 0, y 2 = z 0 + x 2, y 3 = w 1, etc. After the first value, each successive number y i is either copied from a position half as far through the w sequence, or is the previous value added to one value in the ...