Estimation Techniques
Estimation Techniques
Module 2.1
School of Risk & Actuarial Studies
UNSW Business School
Lectorial notes
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Estimation Techniques
Quiz
Define the following concepts:
I Statistic
I Point estimate
I Estimator
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Estimation Techniques
Method of Moments
I How to find a method of moment estimator? Describe all
principal steps of the estimation procedure.
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Estimation Techniques
Method of Moments
Question: Consider X1 , X2 , . . . , Xn i.i.d. and Gamma(, )
find the MME of the parameters of the Gamma distribution.
(+r )
fX (x) = x 1 e x ;
() E [X r ] = r ()
MX (t) = E e tX = t ; Var (X ) = 2
.
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Estimation Techniques
Maximum Likelihood Estimation
I What is a likelihood function, L(|x)?
I Why do we need to introduce log-likelihood function, `(|x)?
I How to obtain a Maximum Likelihood Estimator? Describe all
principal steps of the estimation procedure and conditions.
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Estimation Techniques
Maximum Likelihood Estimation
Consider an i.i.d. sample X1 , X2 , ..., Xn from a Exp() with
observations x1 , x2 , ..., xn .
I What is the likelihood function?
I What is the domain and range of the likelihood function?
I Is the likelihood function continuous?
I Derive the maximum likelihood estimator.
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Estimation Techniques
Maximum Likelihood Estimation
Consider an i.i.d. sample X1 , X2 , ..., Xn from a Uniform(0, ) with
observations x1 , x2 , ..., xn .
I What is the likelihood function?
I What is the domain and range of the likelihood function?
I Is the likelihood function continuous?
I Derive the maximum likelihood estimator.
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Estimation Techniques
Bayesian Estimation
Under the Bayesian framework, explain the following terms
I probability distribution function
I joint density function
I prior distribution
I posterior distribution
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Estimation Techniques
Examples: Bayesian estimation
Example Bayesian estimation: Bernoulli-Beta
I Let X1 , X2 , . . . , XT be i.i.d. Bernoulli(), i.e.,
(Xi | = ) Bernoulli(). Assume the prior density of is
Beta(a, b) so that:
(a + b)
() = a1 (1 )b1 .
(a) (b)
I Find the Bayesian estimator, .
b
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