add a categorical repsonse example

day-5/categorical-response-example.R

@@ -0,0 +1,27 @@
+# categorical
+pkgs <- c("mgcv", "ggplot2", "dplyr", "gratia")
+vapply(pkgs, library, logical(1), character.only = TRUE, logical.return = TRUE,
+       quietly = TRUE)
+
+# Ordered categorical model ocat()
+n_categories <- 4
+su_eg1_ocat <- data_sim("eg1", n = 200, dist = "ordered categorical",
+                        n_cat = n_categories, seed = 2)
+m_ocat <- gam(y ~ s(x0) + s(x1) + s(x2) + s(x3),
+              family = ocat(R = n_categories), data = su_eg1_ocat, method = "REML")
+
+fitted_values(m_ocat)
+
+draw(m_ocat, scales = "fixed")
+
+ds <- data_slice(m_ocat, x2 = evenly(x2))
+fv_ocat <- fitted_values(m_ocat, data = ds)
+
+fv_ocat |>
+  ggplot(aes(x = x2, y = fitted, colour = category, group = category)) +
+  geom_ribbon(aes(ymin = lower, ymax = upper, x = x2,
+                  fill = category, colour = NULL),
+              alpha = 0.2) +
+  geom_line()
+
+head(predict(m_ocat, type = "response", exclude = "s(individual)"))