Final Weekly Task

library(wooldridge)
library(ggplot2)

data("ceosal1")

ceosal1$industry <- with(ceosal1, ifelse(indus    == 1, "Industrial",
                                  ifelse(finance  == 1, "Finance",
                                  ifelse(consprod == 1, "Consumer Products",
                                  ifelse(utility  == 1, "Utilities", "Other")))))

ceosal1$industry <- factor(ceosal1$industry,
                           levels = c("Industrial", "Finance",
                                      "Consumer Products", "Utilities", "Other"))

# Task 1 - Scatterplot with trend line
ggplot(ceosal1, aes(x = sales, y = salary)) +
  geom_smooth(method = "lm", se = TRUE,
              color = "#2166AC", fill = "#AED6F1", linewidth = 1) +
  geom_point(color = "#E74C3C", alpha = 0.65, size = 2.5) +
  labs(
    title    = "CEO Salary vs. Company Sales",
    subtitle = "ceosal1 dataset — Wooldridge",
    x        = "Firm Sales (millions of USD)",
    y        = "CEO Salary (thousands of USD)"
  ) +
  theme_minimal()

# Task 2 - Faceted plot by industry
ggplot(ceosal1, aes(x = roe, y = salary)) +
  geom_smooth(method = "lm", se = FALSE, color = "#27AE60", linewidth = 0.9) +
  geom_point(color = "#8E44AD", alpha = 0.60, size = 2) +
  facet_wrap(~ industry, ncol = 3, scales = "free_y") +
  labs(
    title = "CEO Salary vs. Return on Equity by Industry",
    x     = "Return on Equity (%)",
    y     = "CEO Salary (thousands of USD)"
  ) +
  theme_minimal() +
  theme(strip.text = element_text(face = "bold"))

# Task 3 - Color scale plot
ggplot(ceosal1, aes(x = sales, y = salary, color = roe)) +
  geom_point(size = 3, alpha = 0.80) +
  scale_color_viridis_c(name = "Return on\nEquity (%)", option = "C", direction = -1) +
  labs(
    title = "CEO Salary vs. Sales (Colored by ROE)",
    x     = "Firm Sales (millions of USD)",
    y     = "CEO Salary (thousands of USD)"
  ) +
  theme_minimal()