The following question has been answered on the site and I have been able to work through all of the calculations and found my answers to be the same except for two of them...the standard deviation of the portfolio in the second chart and the portfolio variance in the same chart of the expert answer. (Unfortunately, the expert answer would not copy to this post-reason for including the origial question). The expert answer is showing the standard deviation as 23.180443% and the variance as 5.373330% but these are completely different from what I am calculating on my TI 83 plus. With my calculations I am getting a standard deviation of .1036660943 (10.36660943%) and a variance of .0107466591(1.07466591%). Can you please acknowledge what numbers I need to be using and what calculations I need to be performing in order to get the answer shown or is mine correct? Please help. Thank you.

World Wide Widget Manufacturing, Inc., has decided to invest in some stock. As CFO, you have been asked to review the portfolio. First, you will need to measure the past performance of the investments. Then, measure the past returns risk of the investment. Lastly calculate the average return and risk of the portfolio. What is the average return and standard deviation of returns for these two companies? What is the average return of a portfolio consisting of 60 percent of Company A and 40 percent of company B?

Comapny A	Company B
Year 1	5.23 %	13.51%
Year 2	8.91	-9.35
Year 3	7.32	2.44
Year 4	-15.81	3.12
Year 5	-8.32	14.81
Year 6	25.98	18.36