Exam Completion Time

import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots(figsize=(10, 6), facecolor='#ffffff')
ax.set_facecolor('#ffffff')

np.random.seed(42)
completion_time = np.random.normal(45, 12, 400)

ax.ecdf(completion_time, color='#ec4899', linewidth=2.5)

time_limit = 60
ax.axvline(x=time_limit, color='#dc2626', linestyle='--', linewidth=2, label=f'Time Limit: {time_limit} min')
pct_finished = np.mean(completion_time <= time_limit) * 100
ax.text(time_limit + 1, 0.5, f'{pct_finished:.1f}%\nfinished', fontsize=10, color='#dc2626')

ax.set_xlabel('Completion Time (minutes)', fontsize=12, color='#1f2937')
ax.set_ylabel('Cumulative Probability', fontsize=12, color='#1f2937')
ax.set_title('Exam Completion Time ECDF', fontsize=16, fontweight='bold', color='#1f2937', pad=20)
ax.legend(loc='lower right')
ax.grid(True, alpha=0.3)

for spine in ['top', 'right']:
    ax.spines[spine].set_visible(False)

plt.tight_layout()