Sleep Quality by Age Group ANOVA

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

np.random.seed(1717)

# Sleep efficiency percentage
young_adults = np.random.normal(88, 6, 100)
middle_age = np.random.normal(82, 8, 100)
older_adults = np.random.normal(75, 10, 100)
seniors = np.random.normal(68, 12, 100)

# Clip to valid percentages
young_adults = np.clip(young_adults, 50, 100)
middle_age = np.clip(middle_age, 45, 100)
older_adults = np.clip(older_adults, 40, 100)
seniors = np.clip(seniors, 35, 100)

F_stat, p_value = stats.f_oneway(young_adults, middle_age, older_adults, seniors)

fig, ax = plt.subplots(figsize=(12, 7), facecolor='#ffffff')
ax.set_facecolor('#ffffff')

colors = ['#6CF527', '#27D3F5', '#F5B027', '#F5276C']

parts = ax.violinplot([young_adults, middle_age, older_adults, seniors], 
                       positions=[1, 2, 3, 4], showmeans=True, showmedians=True, widths=0.7)

for i, pc in enumerate(parts['bodies']):
    pc.set_facecolor(colors[i])
    pc.set_alpha(0.6)
    pc.set_edgecolor(colors[i])
    pc.set_linewidth(2)

parts['cmeans'].set_color('#5314E6')
parts['cmeans'].set_linewidth(2.5)
parts['cmedians'].set_color('#1f2937')
for partname in ['cbars', 'cmins', 'cmaxes']:
    parts[partname].set_color('#9ca3af')

# Sleep thresholds
ax.axhline(y=85, color='#22c55e', linestyle='--', alpha=0.7, linewidth=1.5)
ax.axhline(y=70, color='#f97316', linestyle='--', alpha=0.7, linewidth=1.5)
ax.text(4.45, 85, 'Good', fontsize=8, color='#22c55e', va='center')
ax.text(4.45, 70, 'Fair', fontsize=8, color='#f97316', va='center')

labels = ['18-30y', '31-50y', '51-65y', '65+y']

# REM sleep at bottom
rem_pct = ['25%', '22%', '18%', '15%']
means = [young_adults.mean(), middle_age.mean(), older_adults.mean(), seniors.mean()]
for i, (rem, mean, color) in enumerate(zip(rem_pct, means, colors)):
    ax.text(i+1, 32, f'REM:{rem} | μ={mean:.0f}%', ha='center', fontsize=8, color=color)

# Stats at top
stats_text = f"ANOVA: F={F_stat:.2f}, p={p_value:.2e} | Trend: Decline with age"
bbox = dict(boxstyle="round,pad=0.3", facecolor='#f0fdf4', edgecolor='#6CF527', lw=2)
ax.text(0.5, 1.02, stats_text, transform=ax.transAxes, fontsize=10, color='#1f2937',
        ha='center', va='bottom', fontfamily='monospace', bbox=bbox)

ax.set_xticks([1, 2, 3, 4])
ax.set_xticklabels(labels, fontsize=11, color='#1f2937')
ax.set_ylabel('Sleep Efficiency (%)', fontsize=12, color='#1f2937', fontweight='500')
ax.set_title('Sleep Quality Across Age Groups\nPolysomnography Study (N=400)', 
             fontsize=14, color='#1f2937', fontweight='bold', pad=25)

ax.tick_params(colors='#374151')
for spine in ax.spines.values():
    spine.set_color('#e5e7eb')
ax.yaxis.grid(True, color='#f3f4f6', linewidth=0.8)
ax.set_axisbelow(True)
ax.set_ylim(28, 105)

plt.tight_layout()
plt.show()