Likelihood Function Homework: Data, Parameter & Solution

In summary: Your name] In summary, we discussed the likelihood function for a series of independent measurements of the length of a rod. The function represents the probability of obtaining a certain set of measurements given a specific unknown parameter, which in this case is the true length of the rod. We used the Gaussian distribution formula to calculate the likelihood function for each measurement, taking into account the given standard deviation of 5.0 cm.
  • #1
hasan_researc
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Homework Statement




A series of independent measurements of the length of a rod delivers the following
result (units of cm):

{57.0, 49.3, 60.6, 74.5, 58.6, 62.4} (1)

Assume that the measurements are Gaussian distributed, with the standard deviation
of each measurement being 5.0 cm.

(a) What is the likelihood function for each measurement? Identify explicitly the data and the unknown parameter.

Homework Equations



No idea!

The Attempt at a Solution



No idea!
 
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  • #2


Hello,

Thank you for sharing your measurements with us. I would like to help you understand the likelihood function for each measurement.

The likelihood function is a function that represents the probability of obtaining a certain set of measurements given a specific unknown parameter. In this case, the unknown parameter is the true length of the rod.

To calculate the likelihood function for each measurement, we can use the Gaussian distribution formula:

f(x) = (1/σ√2π) * e^(-1/2((x-μ)/σ)^2)

Where:
f(x) is the probability density function
μ is the mean (in this case, the unknown parameter)
σ is the standard deviation (given as 5.0 cm)
x is the measurement value

Plugging in the values from your measurements, we get the following likelihood functions:

f(x1) = (1/5√2π) * e^(-1/2((57.0-μ)/5)^2)
f(x2) = (1/5√2π) * e^(-1/2((49.3-μ)/5)^2)
f(x3) = (1/5√2π) * e^(-1/2((60.6-μ)/5)^2)
f(x4) = (1/5√2π) * e^(-1/2((74.5-μ)/5)^2)
f(x5) = (1/5√2π) * e^(-1/2((58.6-μ)/5)^2)
f(x6) = (1/5√2π) * e^(-1/2((62.4-μ)/5)^2)

I hope this helps you understand the likelihood function for each measurement. If you have any further questions, please let me know.


 

1. What is a likelihood function?

A likelihood function is a statistical tool used to determine the likelihood of a set of data being observed given a certain set of parameters. It is often used in maximum likelihood estimation, where the goal is to find the parameter values that make the observed data most likely.

2. How is a likelihood function calculated?

A likelihood function is calculated by multiplying the probabilities of each data point being observed given the specific parameter values. This can be represented mathematically as L(θ|X) = P(X|θ), where θ represents the parameters and X represents the data.

3. What is the difference between a likelihood function and a probability function?

A likelihood function calculates the probability of data given a set of parameters, while a probability function calculates the probability of parameters given a set of data. In other words, a likelihood function is used to estimate parameters, while a probability function is used to estimate data.

4. How does the likelihood function help in finding the best estimates for parameters?

The likelihood function allows us to compare different sets of parameter values and determine which ones are most likely to have produced the observed data. By maximizing the likelihood function, we can find the parameter values that are most likely to be the true values.

5. Can the likelihood function be used for any type of data?

Yes, the likelihood function can be used for any type of data as long as the data can be expressed in terms of probabilities. However, it is most commonly used with data that follows a specific distribution, such as the normal distribution or the binomial distribution.

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