> x.out <- setx(mod, credit=1)
Error in dta[complete.cases(mf), names(dta) %in% vars, drop = FALSE] :
  incorrect number of dimensions

data=read.table("https://onlinecourses.science.psu.edu/stat504/sites/onlinecourses.science.psu.edu.stat504/files/lesson07/cheese.dat",col.names=c("cheese","response","count"))
data$response=factor(data$response, ordered=T)
fit=polr(response ~ cheese, weights=count, data=data)
summary(fit)
z=summary(fit)$coefficients/summary(fit)$standard.errors
p=(1 - pnorm(abs(z), 0, 1)) * 2 # 2-tailed Wald z tests to test significance of coefficients
p
Anova(fit, type="III")  # likelihood ratio tests for effect of different factors
library(colorRamps)
plot(allEffects(fit),ylab="Response",rescale.axis=F,style="stacked",colors=colorRampPalette(c("white","red"))(9))