An archive the questions from Mark's Summer 2018 Stat 185.

MyOpenMath Homework due 6/13/2018

KBiehler1

Hey all,

I’m having difficulty understanding part B of the final question on tonight’s MyOpenMath homework. I would appreciate any help or solutions you can provide.

Question 5 in the Normal Models assignment states:

3.8 CAPM: The Capital Asset Pricing Model (CAPM) is a financial model that assumes returns on a portfolio are normally distributed. Suppose a portfolio has an average annual return of 14.7% (i.e. an average gain of 14.7%) with a standard deviation of 33%. A return of 0% means the value of the portfolio doesn’t change, a negative return means that the portfolio loses money, and a positive return means that the portfolio gains money.
(please round answers to within one hundredth of a percent)

(a) What percent of years does this portfolio lose money, i.e. have a return less than 0%?

I was able to solve this portion of the question by finding the z-score with the equation: (0-14.7)/33
From that equation I got a z-score of -0.445454545 which I rounded to -0.45. That z-score on the tables is equal to 0.3264, which gave me the answer of 32.64%

(b) What is the cutoff for the highest 15% of annual returns with this portfolio?

I am unsure if I don’t understand the language of this question, or if I am not using the correct equation. If anyone could help explain this, I would appreciate it.

robin

I tried assuming the highest 15% was at 0.85 on the table which correlates to a Z score of 1.03. then plug that into the formula. 1.03 = (x-14.7)/33.