# NOT RUN {
data(wvs94a)
## Random-effects model
random.ma1 <- meta(y=cbind(lifesat, lifecon),
v=cbind(lifesat_var, inter_cov, lifecon_var), data=wvs94a,
model.name="Random effects model")
summary(random.ma1)
## Random-effects model with both population effect sizes fixed at 0
random.ma2 <- meta(y=cbind(lifesat, lifecon),
v=cbind(lifesat_var, inter_cov, lifecon_var), data=wvs94a,
intercept.constraints=matrix(0, nrow=1, ncol=2),
model.name="Effect sizes are fixed at 0")
summary(random.ma2)
## Compare the nested models
anova(random.ma1, random.ma2)
## Fixed-effects model by fixing the variance component at 0
fixed.ma <- meta(y=cbind(lifesat, lifecon),
v=cbind(lifesat_var, inter_cov, lifecon_var), data=wvs94a,
RE.constraints=matrix(0, ncol=2, nrow=2),
model.name="Fixed effects model")
summary(fixed.ma)
## Mixed-effects model
## gnp is divided by 10000 and centered by using
## scale(gnp/10000, scale=FALSE)
mixed.ma1 <- meta(y=cbind(lifesat, lifecon),
v=cbind(lifesat_var, inter_cov, lifecon_var),
x=scale(gnp/10000, scale=FALSE), data=wvs94a,
model.name="GNP as a predictor")
summary(mixed.ma1)
## Mixed-effects model with equal regression coefficients
mixed.ma2 <- meta(y=cbind(lifesat, lifecon),
v=cbind(lifesat_var, inter_cov, lifecon_var),
x=scale(gnp/10000, scale=FALSE), data=wvs94a,
coef.constraints=matrix(c("0.0*Eq_slope",
"0.0*Eq_slope"), nrow=2),
model.name="GNP as a predictor with equal slope")
summary(mixed.ma2)
## Compare the nested models
anova(mixed.ma1, mixed.ma2)
## Plot the multivariate effect sizes
plot(random.ma1, main="Estimated effect sizes and their 95% confidence ellipses",
axis.label=c("Gender difference on life satisfaction",
"Gender difference on life control"))
# }
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