Monthly Electricity Bill Distribution

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

np.random.seed(201)

bills = np.concatenate([
    np.random.normal(80, 20, 300),
    np.random.normal(150, 35, 200),
    np.random.normal(200, 40, 150)
])
bills = bills[(bills > 20) & (bills < 350)]

kde = stats.gaussian_kde(bills)
x = np.linspace(20, 350, 500)
y = kde(x)

colors = ['#1e3a8a', '#3b82f6', '#22d3ee', '#fbbf24', '#f97316', '#dc2626']

fig, ax = plt.subplots(figsize=(12, 6), facecolor='#ffffff')
ax.set_facecolor('#ffffff')

for i in range(len(x)-1):
    norm_val = (x[i] - 20) / 330
    color_idx = int(norm_val * (len(colors) - 1))
    color_idx = max(0, min(color_idx, len(colors)-1))
    ax.fill_between(x[i:i+2], y[i:i+2], alpha=0.6, color=colors[color_idx])

ax.plot(x, y, color='#374151', linewidth=2.5)

thresholds = [(100, 'Low'), (175, 'Medium'), (250, 'High')]
for val, label in thresholds:
    ax.axvline(val, color='#9ca3af', linestyle='--', linewidth=1.5, alpha=0.7)
    ax.text(val+5, max(y)*0.9, label, color='#6b7280', fontsize=9, fontweight='bold')

mean_bill = np.mean(bills)
ax.axvline(mean_bill, color='#374151', linestyle='-', linewidth=2)
ax.text(mean_bill+5, max(y)*0.7, 'Avg: $' + str(int(mean_bill)), color='#374151', fontsize=10, fontweight='bold')

ax.set_xlabel('Monthly Bill ($)', fontsize=12, color='#1f2937', fontweight='500')
ax.set_ylabel('Density', fontsize=12, color='#1f2937', fontweight='500')
ax.set_title('Monthly Electricity Bill Distribution', fontsize=16, color='#1f2937', fontweight='bold', pad=15)

ax.tick_params(colors='#374151', labelsize=10)
for spine in ax.spines.values():
    spine.set_color('#d1d5db')
ax.grid(True, alpha=0.3, color='#e5e7eb')
ax.set_xlim(20, 350)

plt.tight_layout()
plt.show()