Beginner vs Advanced Student Scores

import numpy as np
import matplotlib.pyplot as plt
from scipy.stats import gaussian_kde

np.random.seed(1979)
BG_COLOR = '#0a0a0f'
TEXT_COLOR = 'white'

beginners = np.random.normal(65, 12, 800)
advanced = np.random.normal(85, 8, 600)
beginners = beginners[(beginners >= 30) & (beginners <= 100)]
advanced = advanced[(advanced >= 50) & (advanced <= 100)]

fig, ax = plt.subplots(figsize=(12, 7), facecolor=BG_COLOR)
ax.set_facecolor(BG_COLOR)

x = np.linspace(30, 100, 400)

kde_b = gaussian_kde(beginners)
y_b = kde_b(x)
ax.fill_between(x, y_b, alpha=0.3, color='#F5276C')
ax.plot(x, y_b, color='#F5276C', linewidth=4, alpha=0.3)
ax.plot(x, y_b, color='#F5276C', linewidth=2, label='Beginners (n=%d)' % len(beginners))

kde_a = gaussian_kde(advanced)
y_a = kde_a(x) * -1
ax.fill_between(x, y_a, alpha=0.3, color='#27D3F5')
ax.plot(x, y_a, color='#27D3F5', linewidth=4, alpha=0.3)
ax.plot(x, y_a, color='#27D3F5', linewidth=2, label='Advanced (n=%d)' % len(advanced))

ax.axhline(0, color='#333', linewidth=1.5)

med_b = np.median(beginners)
med_a = np.median(advanced)
ax.axvline(med_b, color='#F5276C', linestyle='--', linewidth=1.5, alpha=0.7)
ax.axvline(med_a, color='#27D3F5', linestyle='--', linewidth=1.5, alpha=0.7)

improvement = med_a - med_b
ax.annotate('', xy=(med_a, 0.02), xytext=(med_b, 0.02),
            arrowprops=dict(arrowstyle='<->', color='#F5B027', lw=2))
ax.text((med_b + med_a)/2, 0.025, '+%.1f pts' % improvement, 
        color='#F5B027', fontsize=11, ha='center', fontweight='bold')

pass_rate_b = (beginners >= 70).sum() / len(beginners) * 100
pass_rate_a = (advanced >= 70).sum() / len(advanced) * 100
stats_text = 'Pass Rate (70+):\nBeginners: %.0f%%\nAdvanced: %.0f%%' % (pass_rate_b, pass_rate_a)
ax.text(0.02, 0.98, stats_text.replace('\n', chr(10)), transform=ax.transAxes, fontsize=10,
        color=TEXT_COLOR, verticalalignment='top', fontfamily='monospace',
        bbox=dict(boxstyle='round,pad=0.5', facecolor='#1a1a2e', edgecolor='#333', alpha=0.9))

ax.set_xlabel('Test Score', fontsize=12, color=TEXT_COLOR, fontweight='500')
ax.set_ylabel('Density', fontsize=12, color=TEXT_COLOR, fontweight='500')
ax.set_title('Student Achievement: Beginner vs Advanced', fontsize=14, 
             color=TEXT_COLOR, fontweight='bold', pad=15)

ax.tick_params(colors='#888', labelsize=10)
for spine in ax.spines.values():
    spine.set_color('#333')

ax.legend(loc='upper right', facecolor='#1a1a2e', edgecolor='#333', 
          labelcolor=TEXT_COLOR, fontsize=10)
ax.set_xlim(30, 100)
plt.tight_layout()
plt.show()