分散化效应

def solve(n_assets, avg_variance, avg_covariance):
    portfolio_variance = avg_variance / n_assets + (n_assets - 1) / n_assets * avg_covariance
    diversification_benefit = avg_variance - portfolio_variance
    return {"资产数量": n_assets, "组合方差": round(portfolio_variance, 4), "分散化收益": round(diversification_benefit, 4)}