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Yule's Q

Source: R/assoc.R
yule_q.Rd

yule_q() computes Yule's Q coefficient of association for a 2x2 contingency table.

Usage

yule_q(x, detail = FALSE, conf_level = 0.95, digits = 3L, .include_se = FALSE)

Arguments

x

A contingency table (of class table).

detail

Logical. If FALSE (default), return the estimate as a numeric scalar. If TRUE, return a named numeric vector including confidence interval and p-value.

conf_level

A number between 0 and 1 giving the confidence level (default 0.95). Only used when detail = TRUE. Set to NULL to omit the confidence interval.

digits

Number of decimal places used when printing the result (default 3). Only affects the detail = TRUE output.

.include_se

Internal parameter; do not use.

Value

Same structure as cramer_v(): a scalar when detail = FALSE, a named vector when detail = TRUE. The p-value tests H0: Q = 0 (Wald z-test).

Details

For a 2x2 table with cells \(a, b, c, d\), Yule's Q is \(Q = (ad - bc) / (ad + bc)\). It is equivalent to the Goodman-Kruskal Gamma for 2x2 tables. The asymptotic standard error is \(SE = 0.5 (1 - Q^2) \sqrt{1/a + 1/b + 1/c + 1/d}\). Standard error formulas follow the DescTools implementations (Signorell et al., 2024); see cramer_v() for full references.

See also

phi(), gamma_gk(), assoc_measures()

Examples

tab <- table(sochealth$smoking, sochealth$sex)
yule_q(tab)
#> [1] -0.02632653