Need help with the Standard Deviation

Fill in the missing information in the following table. Assume that Portfolio AB is 40 percent invested in Stock A. (A negative value should be indicated by a minus sign. Do not round intermediate calculations. Enter your answers as a percent rounded to 2 decimal places.) Year 2012 2013 Annual Returns on Stocks A and B Stock A Stock B 11.0 % 19.0 % 33.0 % (32.0) % (13.0) % 42.0 % 24.0 % 18.0 % 17.0% 30.0 % 14.40% 15.40% % % Portfolio AB 15.80 % (6.00) % 20.00% 2014 20.40% 24.80% 2015 2016 Average return Standard deviation 15.00% %