Calculate Stuart's tau-c statistic, a measure of
association for ordinal factors in a two-way table.
The function has interfaces for a table (matrix) and for single vectors.
a numeric vector or a table. A matrix will be treated as table.
NULL (default) or a vector with compatible dimensions to
confidence level of the interval. If set to
further arguments are passed to the function
Stuart's tau-c makes an adjustment for table size in addition to a correction for ties. Tau-c is
appropriate only when both variables lie on an ordinal scale.
It is estimated by
tau_c = m / n^2 * (P-Q) / (m-1)
where P equals twice the number of concordances and Q twice the number of discordances, n is the total amount of observations and m = min(R, C). The range of tau-c is [-1, 1].
See http://support.sas.com/documentation/cdl/en/statugfreq/63124/PDF/default/statugfreq.pdf, pp. 1739 for the estimation of the asymptotic variance.
a single numeric value if no confidence intervals are requested,
and otherwise a numeric vector with 3 elements for the estimate, the lower and the upper confidence interval
Andri Signorell <email@example.com>
Agresti, A. (2002) Categorical Data Analysis. John Wiley & Sons, pp. 57–59.
Goodman, L. A., & Kruskal, W. H. (1954) Measures of association for cross classifications. Journal of the American Statistical Association, 49, 732-764.
Goodman, L. A., & Kruskal, W. H. (1963) Measures of association for cross classifications III: Approximate sampling theory. Journal of the American Statistical Association, 58, 310-364.
ConDisPairs yields concordant and discordant pairs
Other association measures:
cor (method="kendall") for tau-b,
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