房价回归置信带（高级图表）

def solve():
    import pandas as pd
    import matplotlib.pyplot as plt
    import numpy as np
    
    url = 'https://liangdaima.com/static/data/wooldridge/hprice1.csv'
    df = pd.read_csv(url)
    
    from scipy import stats
    plt.figure(figsize=(10,6))
    x = df['sqrft']
    y = df['price']
    slope, intercept, r_value, p_value, std_err = stats.linregress(x, y)
    x_line = np.linspace(x.min(), x.max(), 100)
    y_pred = slope * x_line + intercept
    plt.scatter(x, y, alpha=0.5, color='blue')
    plt.plot(x_line, y_pred, 'r-', linewidth=2, label=f'回归线 (R^2={r_value**2:.3f})')
    plt.fill_between(x_line, y_pred - std_err*100, y_pred + std_err*100, alpha=0.2, color='red')
    plt.title('房价回归置信区间', fontsize=14)
    plt.xlabel('房屋面积（平方英尺）', fontsize=12)
    plt.ylabel('房价（千美元）', fontsize=12)
    plt.legend()
    plt.grid(alpha=0.3)
    plt.tight_layout()
    plt.show()
    return "可视化代码执行完成"