Business Essay

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Question 5:

The probabilities were assigned using the relative frequency approach.

Define event A as the event that A wins the game. What is P(A)? (0.36)

Let event C be the event that the game ends in a tie. P(B)=0.28

Define event B as the event that flat mate B wins the game. P(B)=0.36

What is the complement of event A? (AC=event B or event C)

The probability of AC is (0.64)

Question 6: Scenario: porker

FAN’S NOTES: Pair=对子;flush=同花色;straight=顺子(in this case, it can only be JQK)

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There are 20 possible outcomes, of which 12 are pairs, 6 are straight and 2 are flushes. Before play begins, the probability that your opponent’s card forms a pair is 0.6.

Now play begins. You pick up your private cards and see that you have the jack of diamonds and the queen of diamonds. The probability that your opponent has a pair is 0.5, the probability of flush is ¼, the probability of straight is ¼.

The common cards is turned over, and it’s the jack of spades. The probability that your opponent has a pair is 0.33.

Given the private cards you were dealt and the common card dealt to you and your opponent, there is a 0 probability that you win, a 0.67 probability that you lose, and a 0.33 probability of tie.

FAN’S NOTES: 0+0.67+0.33=1

Question 7: (data for this question is missing)

N= the event that the user is not a social worker

E=the event that the user sends email to friends every day

O=the event that the user doesn’t send email to friends every day

FAN’s NOTES: in this case, there are two categories – social worker and send email every day.

What is the probability that this randomly selected user doesn’t send email to friends everyday? (0.85)

What is the probability that the randomly selected user is not a social worker who doesn’t send email to friends everyday? (0.41) (joint probability)

What is the probability that a user doesn’t send email to friends every day, given that he is not a social worker? (0.93) (conditional probability)

Events O and N are not independent.

Question 8: 看美景还是看沙漠对于学习和旅游的影响（我上课讲过的例子）

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Question 9: 这道题目的答案没有留下来，但是这道题目的难点在于公式和概念

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