Please comment the following statement
1) The expected return of zero beta security is risk free rate;
2) According to CAPM, the higher the standard deviation, the higher the expected return.
3) As diversification increases, the firm-specific risk of a portfolio approaches 1.
4) Analysts may use regression analysis to estimate the index model for a stock. When doing so, the slope of the regression line is an estimate of the volatility of the asset.