"quantity"exercise:Expected return on securities
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Questions 1:
The joint probability of returns for securities A and B are as follows:
The covariance of the returns between Securities A and B is closest to:
A 、12.
B、14.
C、 13.
Questions 2:
The number of permutations that are possible when choosing 4 objects from a total of 10 objects is closest to:
A 、30.
B 、210.
C、 5,040.
A is correct. First calculate the expected returns on securities A and B with the formula:
Expected return on security A = 0.6 × 25% + 0.4 × 20% = 15% + 8% = 23%
Expected return on security B = 0.6 × 30% + 0.4 × 20% = 18% + 8% = 26%
Then calculate the covariance of returns between securities A and B with the formula:
B is incorrect. In the covariance calculation, it uses the joint probabilities in the wrong positions:
【analysis】
A is incorrect; it is calculated as (10 – 4)!/4! = 6!/4! = 30.
B is incorrect; it is calculated as a combination: 10!/[(10 – 4)! × (4!)] = 10!/(6! × 4!) = 210.
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