Question
(b) Suppose the specialist wants to know the number of suspicious transactions that will need to be
reviewed until reaching the first transaction that will be blocked.
(i) Define the random variable of interest and state how the variable is distributed.
(i) Determine the expected value of the random variable and interpret the expected value in context.
reviewed until reaching the first transaction that will be blocked.
(i) Define the random variable of interest and state how the variable is distributed.
(i) Determine the expected value of the random variable and interpret the expected value in context.
Ask by Norton Huang. in the United States
Mar 21,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
The random variable
represents the number of suspicious transactions reviewed until the first blocked transaction and follows a geometric distribution. The expected value
is
, where
is the probability of a transaction being blocked. This means, on average, you would need to review
transactions to find the first blocked one.
Solution
To solve this problem, let’s break it down step by step.
(i) Define the random variable of interest and state how the variable is distributed.
-
Random Variable Definition:
Letbe the random variable representing the number of suspicious transactions that need to be reviewed until the first transaction that is blocked. -
Distribution:
The random variablefollows a geometric distribution. This is because we are interested in the number of trials (transactions reviewed) until the first success (the first blocked transaction). The geometric distribution is characterized by the probability of success on each trial.
(ii) Determine the expected value of the random variable and interpret the expected value in context.
The expected value
of a geometrically distributed random variable can be calculated using the formula:
where
is the probability of success (the probability that a transaction is blocked).
Interpretation:
- The expected value
represents the average number of suspicious transactions that need to be reviewed before encountering the first blocked transaction. - For example, if
(meaning there is a 10% chance that any given transaction will be blocked), then:
This means, on average, the specialist would need to review 10 suspicious transactions before finding one that is blocked.
If you have a specific value for
, please provide it, and I can calculate the expected value for you.
Answered by UpStudy AI and reviewed by a Professional Tutor
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Bonus Knowledge
The random variable of interest here is the number of suspicious transactions that need to be reviewed until the first transaction is blocked. This variable follows a geometric distribution, characterized by the number of trials until the first success—in this context, “success” means identifying a transaction that gets blocked.
To calculate the expected value of this random variable, we use the formula
, where
is the probability of encountering a suspicious transaction that will be blocked. If, for example, the probability
is 0.2, then the expected number of reviews before blocking one transaction is
. This means that, on average, the specialist will need to review 5 suspicious transactions before blocking one, providing a useful benchmark for resource allocation in the transaction review process.