Additional Evidence of Heteroscedasticity in the Market Model
检验了夏普市场模型的基本假设，特别是异方差性问题，为学术研究者和金融从业者评估该模型的适用性和可靠性提供进一步证据。
Sharpe's market model [29] is widely used both by academic researchers and practitioners in finance, but it cannot be accepted with complete confidence until some of its basic assumptions are tested more thoroughly. The applicability, usefulness, and reliability of the model are functions of its conformity to real data, which in turn depends partly on the unresolved question of heteroscedasticity.