Chapter 7: Problem 3
If the mean-value function of the renewal process \(\mid N(t), t \geq 0\) ) is given by \(m(t)=t / 2, t \geq 0\), then what is \(P(N(5)=0\\} ?\)
Short Answer
Expert verified
Given the mean-value function \(m(t) = \frac{t}{2}\), the probability of zero events occurring at \(t=5\) is:
\[P(N(5)=0) = e^{-\frac{5}{2}}\]
Step by step solution
01
The mean-value function, denoted by \(m(t)\), is the expected number of events that have occurred up to time \(t\). It is given by: \[m(t) = E[N(t)]\] In our case, it is given by the function: \[m(t) = \frac{t}{2}\] #Step 2: Determine the expected number of events at \(t=5\)#
Using the provided mean-value function, we can determine the expected number of events at \(t=5\), which is given by:
\[m(5) = \frac{5}{2}\]
#Step 3: Use the Poisson distribution to estimate the probability#
02
Since we are dealing with a renewal process, we can model the number of events occurring at any given time using the Poisson distribution. The probability mass function of a Poisson distribution is given by: \[P(N(t)=k) = \frac{(\lambda t)^{k}e^{-\lambda t}}{k!}\] Where \(k\) is the number of events, \(\lambda\) is the rate parameter, and \(t\) is the time. #Step 4: Determine the rate parameter of the Poisson distribution#
For the Poisson distribution we are using, the mean is directly proportional to the rate parameter \(\lambda\) and time \(t\).
\[E[N(t)] = \lambda t\]
Using the expected number of events from Step 2, and \(t=5\), we can calculate the rate parameter:
\[\frac{5}{2} = \lambda \cdot 5\]
\[\Rightarrow \lambda = \frac{1}{2}\]
#Step 5: Compute the probability of zero events occurring at \(t=5\)#
03
Using the Poisson distribution and the rate parameter we found in Step 4, we can now compute the probability of zero events occurring at \(t=5\): \[P(N(5)=0) = \frac{[\frac{1}{2}\cdot(5)]^{0}e^{-\frac{1}{2}\cdot(5)}}{0!}\] #Step 6: Calculate and simplify the expression#
We can now simplify the expression from Step 5:
\[P(N(5)=0) = \frac{1^{0}e^{-\frac{5}{2}}}{1}\]
\[P(N(5)=0) = e^{-\frac{5}{2}}\]
#Solution#
Given the mean-value function \(m(t) = \frac{t}{2}\), the probability of zero events occurring at \(t=5\) is:
\[P(N(5)=0) = e^{-\frac{5}{2}}\]
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Mean-Value Function
The mean-value function, often symbolized as \( m(t) \), plays a crucial role in understanding renewal processes. It represents the expected number of events occurring up to a specific time \( t \). To simplify, think of it as the average number of events expected to happen by the time \( t \) has passed.
In the context of the given problem, we see \( m(t) = \frac{t}{2} \). This tells us that for every unit of time, we expect half of an event. Put simply, if \( t = 2 \), you typically anticipate one event to have occurred on average.
In the context of the given problem, we see \( m(t) = \frac{t}{2} \). This tells us that for every unit of time, we expect half of an event. Put simply, if \( t = 2 \), you typically anticipate one event to have occurred on average.
- It's a linear function, implying a constant rate of event occurrence over time.
- The slope \( \frac{1}{2} \) indicates the rate at which events occur per unit time.
- This continuous and predictable pattern aids in planning and analysis of event occurrences.
Poisson Distribution
The Poisson distribution is a pivotal concept when examining the behavior of events happening independently within a fixed interval of time or space. It's most often applied when you deal with rare events.
The probability mass function (PMF) for the Poisson distribution is defined as:\[P(N(t) = k) = \frac{(\lambda t)^k e^{-\lambda t}}{k!}\]where:
The probability mass function (PMF) for the Poisson distribution is defined as:\[P(N(t) = k) = \frac{(\lambda t)^k e^{-\lambda t}}{k!}\]where:
- \( k \) is the number of events or happenings you are calculating the probability for.
- \( \lambda \) is the rate at which these events occur.
- \( t \) is the time interval.
Probability Mass Function
A Probability Mass Function (PMF) is used specifically for discrete random variables. It allows us to calculate the probability that a discrete random variable is exactly equal to some value.
In relation to the Poisson distribution, the PMF is key to determining the likelihood that a certain number of events occur within a given time period. Here's how it works:
In relation to the Poisson distribution, the PMF is key to determining the likelihood that a certain number of events occur within a given time period. Here's how it works:
- The PMF provides the probability for every possible value of a random variable \( k \).
- The sum of these probabilities across all potential values of \( k \) will equal 1, ensuring all conceivable outcomes are accounted for.
- This function is particularly useful in scenarios where the average rate of occurrence is known but occurrences are random.