Warren Buffett has long been known as one of the worlds most successful investors. Using the returns of Berkshire Hathaway stock $($BRK$),$ answer the following questions?

a$.$ What is the fund's alpha using the $3-$ and $4-$factor models, respectively. What does this tell us about risk adjusted returns of the stock?

b$.$ Use the factor loadings from the two models to determin what type of stocks that Berkshire Hathaway is generally investing in$.$ Why?

BRK $3$ Factor: v$9$