您必须关注的CFA一级知识点大剖析 - Quants
1. An analyst gathered information about three economic variables, He noted that whenever variable A increased by one unit, variable B increased by 0.6 units but variable C decreased by 0.6 units. The correlation between variables A and B and the correlation between variables A and C respectively, are closest to:
|
Correlation between variables A and B |
Correlation between variables A and C |
A |
0.6 |
-1.0 |
B |
1.0 |
-1.0 |
D |
1.0 |
-0.6 |
Correct answer =B
Calculate and interpret a sample covariance and a sample correlation coefficient. The relationship between variables A and B is perfect positive correlation (1.0) and the relationship between variables A and C is perfect negative correlation (-1.0).
CORRELATION的含义是什么?a增长1时b增长0.6 他们的相关系数为什么不是0.6? 因为根据题目的意思,是在判断A和B,A和C的相关系数,相关系数是指两者的变化方向,而不是两者的变化幅度关系,如果在两个变量的变化过程中,A上升时,B总是上升,或者A下降时,B总是下降,说明A和B是有效正相关;否则,有效负相关。 题目中的0.6是指两者的变化幅度之间的变化,是指一个变量变化一个单位,另一个变量变化是前一个变量的几倍,这是指Beta系数。 Beta=Cov(A,B)/var(B)=相关系数×标准差(A)/ 标准差(B)
2. An analyst gathered the following information ($ millions) about the performance of a portfolio:
Quarter |
Value at Beginningof Quarter |
Cash Inflow (Outflow) |
Value at End of Quarter |
1 |
2.0 |
0.3 |
2.4 |
2 |
2.4 |
0.2 |
2.6 |
3 |
2.6 |
(0.3) |
3.2 |
4 |
3.2 |
1.0 |
4.0 |
The portfolio's annual time-weighted rate of return is closest to:
A.18%.
B. 29%.
C. 38%.
Correct answer = C
The time-weighted rate of return is calculated by computing the quarterly holding period returns and linking those returns into an annual return:
1.0435 x 1 x 1.3913 x 0.9524 = 1.3827
1.3827 - 1 = 0.3827 or 38.2%
提问:各个季度的收益率是怎么计算出来的 题中的cash flow(outflow) at beginning of quarter是什么意思 是股利吗???关于cash flow(outflow) at beginning of quarter是指Cash flow是指流入的现金流,为正,outflow是指流出的现金流,为负; 因为是在每一季度开始的时候有的cash inflow和cash outflow,所以应该把cash flow加在起初的value上。 Quarter 1: HPR = 2.4 / (2.0 + 0.3) = 1.0435(期初的价值为2,又流入了0.3,所以期初为2.3) Quarter 2: HPR = 2.6 / (2.4 + 0.2) = 1Quarter 3: HPR = 3.2 / (2.6 – 0.3) = 1.3913(期初的价值为2.6,又流出了0.3,所以期初为2.6-0.3=2.3) Quarter 4: HPR = 4.0 / (3.2 + 1.0) = 0.9524time-weighted rate of return = 1.0435 x 1 x 1.3913 x 0.9524-1= 1.3827-1=38.2%这题给的是季度收益率,而不是年化的,所以不用开3次方。
3. What kind of measurement scales for a group of stocks is labeled as “buy”, “held”, “sell”?
A.ordinal scales
B.nominal scales
C.ratio scales
Correct answer = B
根据原版书上的定义:Nominal scales represent the weakest level of measurement. They categorize data but do not rank them. “buy”, “held”, “sell”并没有对categorize data排序,没有好坏之分,但是ordinal scales是对categorize data有好坏之分的,比如说评级。
4. 有高峰肥尾的情况吗?不是很理解
Solution:Leptokuritic尖峰现象(Kurtsis>3),此时峰高,尾粗,此时,风险较大;但是,t分布则是峰低,尾;Kurtsis>3,且skew<0,风险是**的。
5. 单个收益率的计算
Notes:
1) 一般情况下,考试中的单利用t/360,复利用t/365
2) 计算利息的convention: 30/360, days/365, days/360
6. 各种收益率的联系和转换
1) HPY是一期的收益率概念;r BD, r MM, EAY是年化的收益率;BEY是年化的收益率,但是计算惯例是半年计一次息。
2) r BD是单利,以face value为基础(即face value是分母);r MM是单利,以PV为基础(即PV是分母);EAR是复利。
7. The Harmonic Mean
调和平均很重要的一个用法就是用于测算平均成本。当投资属于持续期限并且每个期限内投资数额相等的情况下可以使用调和平均方法。比如一个投资者两个月各买进一只股票,每月投资1000元,股票价格分别为¥10和¥15,求股票价格的平均成本。该题可以用调和平均的方法:2/[(1/10)+(1/15)]=12;另外需要注意的是调和平均<几何平均<代数平均.
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