You have collected the following returns data: year 2018 return=5%; year 2019 return=-3%; year 2020 return=10%. What is the sample standard deviation for this security? 4.34% 5.35% 6.56% 8.60% Stock X has a Beta of 0.5 and Stock Y has a beta of 1.8. What is the beta of a $5,000 portfolio that has $4,000 invested in stock X and the remainder invested in stock Y? 0.55 0.62 O 0.71 O 0.76