ci.yule: Confidence intervals for generalized Yule coefficients

In statpsych: Statistical Methods for Psychologists

Confidence intervals for generalized Yule coefficients

Description

Computes confidence intervals for four generalized Yule measures of association (Yule Q, Yule Y, Digby H, and Bonett-Price Y*) using a transformation of a confidence interval for an odds ratio with .5 added to each cell frequency. This function requires the frequency counts from a 2 x 2 contingency table for two dichotomous variables. Digby H is sometimes used as a crude approximation to the tetrachoric correlation. Yule Y is equal to the phi coefficient only when all marginal frequencies are equal. Bonett-Price Y* is a better approximation to the phi coefficient when the marginal frequencies are not equal.

Usage

ci.yule(alpha, f00, f01, f10, f11)

Arguments

alpha	alpha level for 1-alpha confidence
f00	number of participants with y = 0 and x = 0
f01	number of participants with y = 0 and x = 1
f10	number of participants with y = 1 and x = 0
f11	number of participants with y = 1 and x = 1

Value

Returns a 1-row matrix. The columns are:

• Estimate - estimate of generalized Yule coefficient

• SE - standard error

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Bonett2007statpsych

Examples

ci.yule(.05, 229, 28, 96, 24)

# Should return:
#      Estimate         SE         LL        UL
# Q:  0.3430670 0.13280379 0.06247099 0.5734020
# Y:  0.1769015 0.07290438 0.03126603 0.3151817
# H:  0.2619244 0.10514465 0.04687994 0.4537659
# Y*: 0.1311480 0.05457236 0.02307188 0.2361941

statpsych documentation built on Sept. 11, 2024, 7:42 p.m.