https://zh.paraquee.com/post/suppose-an-analyst-conducts-event-analysis-according-to-the-market-model-ri-a-b-r-m-e-i-i-is-a-company-m-is-the-market-portfolio-a-001-b-05-if-the-market-rises-by-1-on-that-day-how-much-will-the-expected-return-of-company-i-rise