Assignment 6: Data Visualization - Employee Attrition Analysis

1) Histogram: Distribution of Employee Satisfaction

ggplot(HR, aes(x = satisfaction_level)) +
  geom_histogram(bins = 20, fill = "steelblue", color = "white") +
  labs(
    title = "Employee Satisfaction Clusters at Low and High Levels",
    x = "Satisfaction Level",
    y = "Count"
  ) +
  theme_minimal()

Analysis:
Satisfaction is not evenly distributed; the clustering suggests different employee experience groups that may relate to turnover.

2) Box Plot: Last Evaluation Scores

ggplot(HR, aes(y = last_evaluation)) +
  geom_boxplot(fill = "darkorange") +
  labs(
    title = "Evaluation Scores Are Generally High With Few Low Outliers",
    y = "Last Evaluation Score"
  ) +
  theme_minimal()

Analysis:
Most evaluation scores are high, so attrition likely depends on factors beyond just low performance.

3) Comparative Box Plot: Monthly Hours by Department

ggplot(HR, aes(x = .data[[dept_col]], y = .data[[hours_col]])) +
  geom_boxplot(fill = "orange") +
  labs(
    title = "Monthly Work Hours Differ Meaningfully Across Departments",
    x = "Department",
    y = "Average Monthly Hours"
  ) +
  theme_minimal() +
  theme(axis.text.x = element_text(angle = 45, hjust = 1))

Analysis:
Some departments show higher typical hours and wider variation, which could connect to workload and burnout risk.

4) Pie Chart of Frequencies: Attrition by Salary Level

salary_attrition <- HR %>%
  filter(left == 1) %>%
  count(salary)

ggplot(salary_attrition, aes(x = "", y = n, fill = salary)) +
  geom_col(width = 1, color = "white") +
  coord_polar("y") +
  labs(
    title = "Among Employees Who Left, Lower Salary Levels Are More Common",
    fill = "Salary"
  ) +
  theme_void()

Analysis:
Within the employees who left, lower salary categories make up a larger share, suggesting compensation relates to retention.

5) Bar Plot of Averages: Average Satisfaction by Department

avg_satisfaction <- HR %>%
  group_by(dept = .data[[dept_col]]) %>%
  summarise(avg_sat = mean(satisfaction_level), .groups = "drop")

ggplot(avg_satisfaction, aes(x = dept, y = avg_sat)) +
  geom_col(fill = "steelblue") +
  labs(
    title = "Average Satisfaction Varies Across Departments",
    x = "Department",
    y = "Average Satisfaction Level"
  ) +
  theme_minimal() +
  theme(axis.text.x = element_text(angle = 45, hjust = 1))