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samplestat >> samplestat > ST_trustarea

ST_trustarea

Determines the range of dispersion of the mean.

Calling Sequence

trustval = ST_trustarea(v, p)

Parameters

v:

vector of numerical values

p:

statistical confidence level (%) as a string or the level of significance (alpha) as a decimal value, "95%", "99%", "99.9%" or 0.05, 0.01, 0.001 resp (see examples).

trustval:

trust area, range of dispersion of the mean.

Description

"ST_trustarea" determine the range of dispersion of the mean. It describes the quality of the mean and indicates the range of dispersion of the mean and not of the raw values as the stray area does.

\begin{eqnarray}
T = s \cdot t \\
T_{\bar{x}} = T/ \sqrt{n}
\end{eqnarray}

T: stray area of values; s: sample standard deviation; t: student factor (dependent on statistical confidence level P% and degree of freedom f=n-1 with n: number of values)

E.g. if trustval = 1.4 at p = 95% with a mean = 10,0 the mean for the whole population will stray with a confidence of 95% at about 10.0 +/- 1.4.

Examples

v = [6 8 14 12 5 15];
mean(v) // = 10.
ST_trustarea(v, "95%") // = 4.4514
ST_trustarea(v, 0.05)  // = 4.4514

See also

Authors

Bibliography

R. Kaiser, G. Gottschalk; "Elementare Tests zur Beurteilung von Meßdaten", BI Hochschultaschenbücher, Bd. 774, Mannheim 1972.


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