Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Likelihood


Related Topics

In the News (Mon 23 Nov 09)

  
  Likelihood function - Wikipedia, the free encyclopedia
For a likelihood function of more than one parameter, it is sometimes possible to write some parameters as functions of other parameters, thereby reducing the number of independent parameters.
Attempting to interpret the likelihood of a hypothesis given observed evidence as the probability of the hypothesis is a common error, with potentially disastrous real-world consequences in medicine, engineering or jurisprudence.
The likelihood function is not a probability density function -- for example, the integral of a likelihood function is not in general 1.
en.wikipedia.org /wiki/Likelihood_function   (787 words)

  
 Maximum likelihood - Wikipedia, the free encyclopedia
Likelihood of different proportion parameter values for a binomial process with t = 3 and n = 10; the ML estimator occurs at the mode with the peak (maximum) of the curve.
When maximising the likelihood, we may equivalently maximise the log of the likelihood, since log is a continuous strictly increasing function over the range of the likelihood.
Maximum likelihood estimators achieve minimum variance (as given by the Cramer-Rao lower bound) in the limit as the sample size tends to infinity.
en.wikipedia.org /wiki/Maximum_likelihood   (1223 words)

  
 8.2.3.3. Likelihood ratio tests
Likelihood functions for reliability data are described in Section 4.
Calculate the maximum likelihood of the sample data based on an assumed distribution model (the maximum occurs when unknown parameters are replaced by their maximum likelihood estimates).
The unrestricted likelihood of the data is the product of the two likelihoods, with 4 unknown parameters (the shape and characteristic life for each vendor population).
www.itl.nist.gov /div898/handbook/apr/section2/apr233.htm   (677 words)

  
 Definition: Likelihood ratio
The likelihood ratio incorporates both the sensitivity and specificity of the test and provides a direct estimate of how much a test result will change the odds of having a disease.
The likelihood ratio for a positive result (LR+) tells you how much the odds of the disease increase when a test is positive.
The pre-test odds are usually related to the prevalence of the disease, though you might adjust it upwards or downwards depending on characteristics of your overall patient pool or of the individual patient.
www.childrens-mercy.org /stats/definitions/likelihood.htm   (741 words)

  
 FindLaw for Legal Professionals - Case Law, Federal and State Resources, Forms, and Code
Instead, this factor is only relevant to the extent that it bears upon the likelihood that consumers will be confused by the alleged infringer's mark (or to the extent that a court wishes to consider it as an equitable con- sideration).
Likelihood of confusion is determined on the basis of a "reasonably prudent consumer." Dreamwerks, 142 F.3d at 1129; Sleekcraft, 599 F.2d at 353.
Although the dis- trict court did not address this issue, irreparable injury may be presumed from a showing of likelihood of success on the mer- its of a trademark infringement claim.
laws.lp.findlaw.com /9th/9856918.html   (12522 words)

  
 [No title]
In cases where there is a significant likelihood that the alien will be removed in the reasonably foreseeable future, the Supreme Court's decision did not question the Service's authority to detain an lien under section 241(a)(6) of the Act beyond the six-month period, pursuant to the existing detention standards in 8 CFR 241.4.
In appropriate cases, the rule provides for the HQPDU to advice the Department of State of the alien's contention that his or her removal is not reasonably foreseeable, and to request the assistance and guidance of that Department in evaluating the likelihood of the alien's removal under the circumstances.
The alien may submit any evidence or information that he or she believes shows there is no significant likelihood he or she be removed in the reasonably foreseeable future, or that he or she has not violated the order of supervision.
jurist.law.pitt.edu /terrorism/terrorismregnov14.htm   (13621 words)

  
 Maximum Likelihood
The three main components of the statistical approach are (i) the data, (ii) a model describing the probability of observing the data, and (iii) a criterion that allows us to move from the data and model to an estimate of the parameters of the model.
The likelihood function is obtained by multiplying the probability function for each toss of the coin.
Here, the likelihood calculated under the null hypothesis is in the numerator and the likelihood calculated under the alternative hypothesis is in the denominator.
www.sciencemag.org /feature/data/phylo/coin/coin.html   (1384 words)

  
 Maximum Likelihood
Likelihood: The likelihood function is used to obtain maximum likelihood estimates (MLEs) of parameters and is the probabiity of the observed sequences as a function
The likelihood ratio test statistic is -2logL = 117.946, which is asymptotically c2 distributed under the null hypothesis with 1 degrees of freedom.
The likelihood ratio test statistic is -2logL = 32.582, which is asymptotically c2 distributed under the null hypothesis with 3 degrees of freedom.
ucjeps.berkeley.edu /bryolab/ib200/maximumlikelihood.html   (2941 words)

  
 [No title]
Therefore, in discerning the likelihood of dumping standard under US law, the statute, SAA, and Sunset Policy Bulletin are “inseparable and should not be read independently from each other when evaluating the overall conformity of the law with WTO obligations.” The statutory provision, 19 USC.
The likelihood determination required by Article 11.3 must be based on “all relevant evidence,” not on “the mechanistic application of presumptions.” Ultimately, however, the Appellate Body did not decide whether the Sunset Policy Bulletin is inconsistent with Article 11.3 as such.
Therefore, in evaluating whether the Commission’s likelihood of injury determination in the sunset review of OCTG from Argentina was consistent with Article 11.3, the panel must consider whether the Commission based its determination on positive evidence and examined the facts objectively.
www.wto.org /english/tratop_e/dispu_e/268r_d_e.doc   (10485 words)

  
 Maximum-Likelihood Template Matching
Inasmuch as the likelihood function measures the probability that each position is an instance of the template, error and uncertainty cause the likelihood-function peak that corresponds to that position to be spread over some volume of the pose space.
Integration of the likelihood function under the peak yields an improved measure of the quality of the peak as a location of the template.
In a stereoscopic or tracking application, the probability of failure to detect the correct position of the template is estimated in a procedure that includes a comparison of the integral of the likelihood under the most likely peak to the integral of the likelihood in the remainder of the pose space.
www.nasatech.com /Briefs/Feb02/NPO21026.html   (707 words)

  
 Maximum Likelihood
To calculate the likelihood for site j, we have to consider all the possible scenarios by which the nucleotides present at the tips of the tree could have evolved.
So the likelihood for a particular site is the summation of the probablilities of every possible reconstruction of ancestral states, given some model of base substitution.
Since the individual likelihoods are extremely small numbers it is convenient to sum the log likelihoods at each site and report the likelihood of the entire tree as the log likelihood.
www.icp.ucl.ac.be /~opperd/private/max_likeli.html   (774 words)

  
 Likelihood   (Site not responding. Last check: 2007-11-06)
B)/P(A) are likelihood functions for B given A.
The first use of "likelihood" in the sense explained here and the distinction between likelihood and probability were first made by R.A. Fisher in his paper "On the mathematical foundations of theoretical statistics" (1922).
This is because integration of the likelihood density function L is performed over all possible values of the model parameters (in this case, p
www.yotor.com /wiki/en/li/Likelihood.htm   (745 words)

  
 MLE (Maximum Likelihood) Parameter Estimation
The idea behind maximum likelihood parameter estimation is to determine the parameters that maximize the probability (likelihood) of the sample data.
From a statistical point of view, the method of maximum likelihood is considered to be more robust (with some exceptions) and yields estimators with good statistical properties.
Although the methodology for maximum likelihood estimation is simple, the implementation is mathematically intense.
www.weibull.com /AccelTestWeb/mle_maximum_likelihood_parameter_estimation.htm   (610 words)

  
 Maximum Likelihood Estimation for the Lognormal Distribution   (Site not responding. Last check: 2007-11-06)
chapter, maximum likelihood estimation works by developing a likelihood function based on the available data and finding the values of the parameter estimates that maximize the likelihood function.
Another method of finding the parameter estimates involves taking the partial derivatives of the likelihood equation with respect to the parameters, setting the resulting equations equal to zero and solving simultaneously to determine the values of the parameter estimates.
The log-likelihood functions and associated partial derivatives used to determine maximum likelihood estimates for the lognormal distribution are covered in the
www.weibull.com /LifeDataWeb/maximum_likelihood_estimation_log.htm   (122 words)

  
 Integrated likelihood methods for eliminating nuisance parameters, James O. Berger, Brunero Liseo, Robert L. Wolpert
Perhaps the least studied approach is elimination of nuisance parameters through integration, in the sense that this is viewed as an almost incidental byproduct of Bayesian analysis and is hence not something which is deemed to require separate study.
The problems associated with the use of profile likelihood methods appear to be due to the relatively large number of nuisance parameters.
We are somewhat concerned with the apparent double use of the data in the definitions of Lest and L est (using the data once in the likelihood function and again in the weight function for integration).
projecteuclid.org /Dienst/UI/1.0/Summarize/euclid.ss/1009211804   (1839 words)

  
 1.3.6.5.2. Maximum Likelihood
Maximum likelihood estimation begins with the mathematical expression known as a likelihood function of the sample data.
Loosely speaking, the likelihood of a set of data is the probability of obtaining that particular set of data given the chosen probability model.
Those values of the parameter that maximize the sample likelihood are known as the maximum likelihood estimates.
www.itl.nist.gov /div898/handbook/eda/section3/eda3652.htm   (583 words)

  
 Likelihood ratchet
As well, tests on a previously published data set that establishes the presence of 'tree islands' under maximum likelihood demonstrated that the algorithm identifies the same tree islands in a shorter amount of time than by using stepwise addition.
The likelihood landscape may be structured in such a way that this starting tree is incongruent with the generating tree, e.g.
The concepts behind the 'Likelihood Ratchet' are dealt with more deeply in a PDF that you can find here.
www.sfu.ca /~rvosa/likelihoodratchet   (1041 words)

  
 Stats: Maximum likelihood estimation
Maximum likelihood is an approach that looks at a large class of distributions and then chooses the "best" distribution.
The log of the likelihood function often simplifies many of the calculations, and if you find the maximum of the log likelihood that also has to be the maximum of the likelihood itself.
I won't show all the equations, but the maximum likelihood estimate of mu ends up equalling the sample mean and the maximum likelihood estimate of sigma ends up equalling, not the sample standard deviation exactly, but something very close where you replace n-1 with n in the formula.
www.cmh.edu /stats/ask/mle.asp   (611 words)

  
 Aptech Systems, Inc. - Constrained Maximum Likelihood
The likelihood ratio of the TGARCH(1,1) over the GARCH(1,1) model, in which the errors are assumed to have a Normal distribution, is 9.9665 with 1 degree of freedom.
The likelihood ratio statistic for the GARCH(1,1) model over an ordinary least squares model is 75.2043 with 4 degrees of freedom, which is highly significant and is strong evidence for the GARCH specification of the stock index.
Among them are the usual standard errors and t-statistics, confidence limits by inversion of the Wald statistic or the likelihood ratio statistic, Bayesian limits by the method of weighted likelihood bootstrap, as well as the usual bootstrap method.
www.aptech.com /ga_cml.html   (627 words)

  
 Likelihood: theory and application to structure refinement
The parameters of this likelihood function are the mean and standard deviation we assume for the Gaussian probability distribution.
The principle of maximum likelihood is quite intuitive, and it leads to useful results, but you might argue that there is a logical problem.
The likelihood function is the probability of the data given the model (p(data;model), in more formal notation), but we tend to think of it as the probability that the model is a good reflection of reality, given the data (p(model;data)).
www-structmed.cimr.cam.ac.uk /Course/Likelihood/likelihood.html   (5356 words)

  
 Computing Papers on Likelihood   (Site not responding. Last check: 2007-11-06)
Here we consider maximum Likelihood (ML) estimation of from incomplete data, i.e., problems in which the image, which is drawn from a Gibbs prior, is observed indirectly through some degradation or blurring process.
As is well known, however, direct use of the Likelihood as a scoring function causes dicult problems especially when the length of a speech segment varies depending on the hypothesis as in word-spotting, and some kind of normalization is indispensable.
In this paper, a new method of Likelihood normalization using an ergodic HMM is presented, and its performance is compared with those of conventional ones.
computing.breinestorm.net /Likelihood   (765 words)

  
 Definition of Method of maximum likelihood
In statistics, the method of maximum likelihood, pioneered by geneticist and statistician Sir Ronald A. Fisher, is a method of point estimation, that uses as an estimate of an unobservable population parameter the member of the parameter space that maximizes the likelihood function.
Let X denote the random variable observed (which in general will not be scalar-valued, but often will be a vector of probabilistically independent scalar-valued random variables).
Taking the logarithm of the likelihood is so common that the term log-likelihood is commonplace among statisticians.
www.wordiq.com /definition/Method_of_maximum_likelihood   (535 words)

  
 likelihood --  Britannica Concise Encyclopedia - The online encyclopedia you can trust!
A slight amount of stimulation of the hallucinated sense may enhance the likelihood of the hallucination's appearance.
In genetics, for example, probability is used to estimate the likelihood for brown-eyed parents to produce a blue-eyed child (see Heredity).
Suggests that the increased likelihood of lawsuits has artificially increased the importance of attorneys within the workplace.
www.britannica.com /ebc/article-9370228?tocId=9370228   (737 words)

  
 Likelihood Ratios   (Site not responding. Last check: 2007-11-06)
Likelihood Ratios are a means of expressing the performance of diagnostic tests.
They allow health care providers to estimate the odds of disease given the results of test information (history items, physical exam, lab or radiologic tests) and some knowledge of the baseline (or pre-test) odds of disease.
Disclaimer: We make no guarantee as to the accuracy of the test information provided or to whether it represents the most recent or highest quality data for a given topic.
www.med.unc.edu /medicine/edursrc/lrmain.htm   (127 words)

  
 Likelihood Ratio Test   (Site not responding. Last check: 2007-11-06)
variables, was selected in preference to logistic regression for the analyses, because it has the advantage of calculating the likelihood ratio test for each...
A likelihood-ratio test is a statistical test relying on a test statistic computed by taking the ratio of the maximum value of the likelihood function under the constraint of the null hypothesis to the maximum with that constraint relaxed.
If that ratio is Λ and the null hypothesis holds, then for commonly occurring families of probability distributions, −2 log Λ has a particularly handy asymptotic distribution.
www.wikiverse.org /likelihood-ratio-test   (638 words)

  
 Likelihood ratios
In the language of clinical epidemiology, we take our initial assessment of the likelihood of disease ("pre-test probability"), do a test to help us shift our suspicion one way or the other, and then determine a final assessment of the likelihood of disease ("post-test probability").
The "positive likelihood ratio" (LR+) tells us how much to increase the probability of disease if the test is positive, while the "negative likelihood ratio" (LR-) tells us how much to decrease it if the test is negative.
The decision to order a test is also based on our initial assessment of the likelihood of the target disorder, and how important it is to rule-in or rule-out disease.
www.poems.msu.edu /EBM/Diagnosis/LR.htm   (580 words)

  
 Likelihood functions based on parameter-dependent functions, Thomas A. Severini   (Site not responding. Last check: 2007-11-06)
The properties and construction of marginal and conditional likelihood functions based on parameter-dependent functions are studied.
may be taken to be functions of the maximum likelihood estimators is considered and approximations to the resulting likelihood functions are presented.
[24] Severini, T.A. (2000b) The likelihood ratio approximation to the conditional distribution of the maximum likelihood estimate in the lattice case.
projecteuclid.org /Dienst/UI/1.0/Summarize/euclid.bj/1089206405   (622 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.