Data simulated from a probit model with a quadratic trend. The data are described in Example 2 of Liu and Zhang (2017).
data(df1)
A data frame with 2000 rows and 2 variables.
x The predictor variable.
y The response variable; an ordered factor.
Liu, Dungang and Zhang, Heping. Residuals and Diagnostics for Ordinal Regression Models: A Surrogate Approach. Journal of the American Statistical Association (accepted).
head(df1)#> y x #> 1 2 5.629381 #> 2 3 6.048645 #> 3 2 3.297068 #> 4 2 3.690209 #> 5 2 5.523061 #> 6 2 4.988184