Lloyd S. Nelson
Abstract
A procedure for sequentially recomputing the mean and standard deviation of a weighted series of numbers as new values are added is given by Hanson [2]. To accommodate the most frequently occurring situation, Cotton [1] expressed Hanson's formulas in terms of unit weights. The result is accurate for updating the mean. However, for updating the standard deviation, Cotton chose to use Hanson's eq. (14), which Hanson rejected as being inaccurate when the new value is close to the mean.
- 1 Cotton, I.W. Remark on stably updating mean and standard deviation. Comm. ACM 18, 8 (Aug. 1975), 458; Corrigendum, Comm. ACM 18, 10 (Oct. 1975), 591. Google Scholar
Digital Library
- 2 Hanson, R.J. Stably updating mean and standard deviation of data. Comm. ACM 18, 1 (Jan. 1975), 57-58. Google ScholarDigital Library
- 3 Youngs, E.A., and Cramer, E.M. Some results relevant to choice of sum and sum-of-product algorithms. Technometrics 13, 3 (Aug. 1971), 657-665.Google ScholarCross Ref
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