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.