a) Consider the following annual rate of returns of Digi and Celcom: Year 2002 2003 2004 2005 2006 Digi -16.8% 49.9% 17.6% -26.0% 23.4% Celcom -19.0% 48.0% 4.2% 16.1% -6.0% Which stock appears to be better based on expected return? Which stock appears to be better based on standard deviation? (10 marks) b) What happens to the risk of a portfolio if assets with very low correlations (even negative correlations) are combined