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Errors, outliers
  From a generated or supplied sample, calculates some common statistics and detects a possible outlier.
2024.May.21 01:21:40
n Sample size (number of observations).
Data source (“G” or “S”) Data: generated; or supplied by user. •
μ, σ (for G) Mean and standard deviation — ignored if "S".
ntrial, .seed (for G) No. of trials and seed — ignored if "S". •
Supplied data, X (for S) User-supplied data (n must always match them !) — ignored if "G". •
Outlier ? Outlier (?), smallest or largest, to be assessed.
P % Probability for interval for μ. •
Show values Shows the coordinates of the graph. •
  From a randomly generated (G) or user-supplied (S) sample (set of observations), calculates some common statistics: average (x-bar), standard deviation (s), average deviation (δ).
 The graph shows: for G, δ simulated for random samples of size 2k trials, with (integer) k = 1..log2(ntrial) (log2100000 = 16.6 → 16); for S, the user data, without the (possible) outlier.
 An extreme (smallest or largest) value in the sample is assessed to estimate whether it is an outlier (to be rejected).
 The decision on what is an outlier is a delicate question. See, for example, Barnett and Lewis [1998].
 Excel:  t = Studinv([(1+prob)/2, ν] becomes TINV[(1-prob, ν] Typically, ν = n − 1. (Here, n had already been reduced, so ν = noriginal − 2 .)
 Other suggested data: 26.6 26.8 26.2 26.9 27.1 27.0 (smallest)   26.6 26.9 26.7 26.6 26.7 26.6 (largest)
References: Plate: Errth08804

• Scuro, Sante R.: Error theory.pdf (Texas A&M Univ.). • Err. analysis (P. C. Eklund, PennState U.). • Petridis, A. (Drake Univ.). • Wolfs, F., see "Error analysis" (Univ. of Rochester).

• Weisstein, Eric W., "Error propagation". From MathWorld — a Wolfram Web Resource (accessed 2008-08-04).

• Barnett, Vic and Toby Lewis, 1998, "Outliers in statistical data", 3.rd ed. (=1994, 1978), Wiley, New York, NY (USA). (At ISEG Library: 1994.)

• Bevington, Philip R. and D. Keith Robinson, 2003, "Data reduction and error analysis for the physical sciences", 3.rd ed., McGraw-Hill, New York, NY (USA).

• Google search: simulation "Monte Carlo" "Chemical Engineering"…

• Kurtosis, skewness.xls • Descriptive statistics (SAS v7 doc., Oklahoma State Univ., Stillwater).

• Student's t (this site).

• Taylor, John R., 1997, "An introduction to error analysis", 2.nd ed., Univ. Sci. Books (USB), Sausalito, CA (USA) (intro IE).

• [Lyons, 1991] • [J. K. Taylor, 1987]

• Weisstein, Eric W., "Student's t-distribution". From MathWorld — a Wolfram Web Resource (accessed 2008-08-04).

• Chauvenet, William, 1820–1870 ("Chauvenet's criterion").

• 1805-08-04: Hamilton, Sir William Rowan, birthday.

 
 
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Created: 2008-08-04 — Last modified: 2009-09-17