Stress and anxiety among nonclinical women in Townsville, Queensland, Australia.
Usage
data("StressAnxiety", package = "betareg")
Format
A data frame containing 166 observations on 2 variables.
stress
score, linearly transformed to the open unit interval (see below).
anxiety
score, linearly transformed to the open unit interval (see below).
Details
Both variables were assess on the Depression Anxiety Stress Scales, ranging from 0 to 42. Smithson and Verkuilen (2006) transformed these to the open unit interval (without providing details about this transformation).
Source
Example 2 from Smithson and Verkuilen (2006) supplements.
References
Smithson M, Verkuilen J (2006). A Better Lemon Squeezer? Maximum-Likelihood Regression with Beta-Distributed Dependent Variables. Psychological Methods, 11(7), 54–71.
See Also
betareg, MockJurors, ReadingSkills
Examples
library("betareg")data("StressAnxiety", package ="betareg")StressAnxiety<-StressAnxiety[order(StressAnxiety$stress),]## Smithson & Verkuilen (2006, Table 4)sa_null<-betareg(anxiety~1|1, data =StressAnxiety, hessian =TRUE)sa_stress<-betareg(anxiety~stress|stress, data =StressAnxiety, hessian =TRUE)summary(sa_null)
Call:
betareg(formula = anxiety ~ 1 | 1, data = StressAnxiety, hessian = TRUE)
Quantile residuals:
Min 1Q Median 3Q Max
-0.8377 -0.8377 -0.4467 0.6217 3.2396
Coefficients (mean model with logit link):
Estimate Std. Error z value Pr(>|z|)
(Intercept) -2.24396 0.09879 -22.71 <2e-16 ***
Phi coefficients (precision model with log link):
Estimate Std. Error z value Pr(>|z|)
(Intercept) 1.796 0.123 14.6 <2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Type of estimator: ML (maximum likelihood)
Log-likelihood: 239.4 on 2 Df
Number of iterations in BFGS optimization: 9