StressAnxiety {betareg} | R Documentation |
Stress and anxiety among nonclinical women in Townsville, Queensland, Australia.
data("StressAnxiety")
A data frame containing 166 observations on 2 variables.
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).
Example 2 from http://psychology3.anu.edu.au/people/smithson/details/betareg/betareg.html
Smithson, M., and Verkuilen, J. (2006). A Better Lemon Squeezer? Maximum-Likelihood Regression with Beta-Distributed Dependent Variables. Psychological Methods, 11(7), 54–71.
betareg
, MockJurors
, ReadingSkills
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) summary(sa_stress) AIC(sa_null, sa_stress) 1 - as.vector(logLik(sa_null)/logLik(sa_stress)) ## visualization attach(StressAnxiety) plot(jitter(anxiety) ~ jitter(stress), xlab = "Stress", ylab = "Anxiety", xlim = c(0, 1), ylim = c(0, 1)) lines(lowess(anxiety ~ stress)) lines(fitted(sa_stress) ~ stress, lty = 2) lines(fitted(lm(anxiety ~ stress)) ~ stress, lty = 3) legend("topleft", c("lowess", "betareg", "lm"), lty = 1:3, bty = "n") detach(StressAnxiety) ## see demo("SmithsonVerkuilen2006", package = "betareg") for more details