t	A,%	B,%	C,%	D,%	Mkt, %
1	18.56	18.23	12.82	12.43	12.28
2	15.27	18.24	15.82	13.45	5.99
3	14.12	14.71	12.58	4.32	12.41
4	-1.57	-6.56	-9.36	-8.54	-4.48
5	13.16	9.12	12.45	12.21	13.41

Use this data for problems 3a-3b The annual returns for securities A,B,C,D and the Market (S&P 500) are shown below.

3b. Calculate the portfolio standard deviation if you put 30% of your money in A and 70% in B. Show your work