{"id":339,"date":"2017-05-05T19:19:00","date_gmt":"2017-05-05T19:19:00","guid":{"rendered":"http:\/\/sites.warnercnr.colostate.edu\/gwhite\/?page_id=339"},"modified":"2017-05-05T19:19:00","modified_gmt":"2017-05-05T19:19:00","slug":"mixture-distributions","status":"publish","type":"page","link":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/mixture-distributions\/","title":{"rendered":"Mixture Distributions"},"content":{"rendered":"

Contents<\/a> – Index<\/a><\/span><\/p>\n

\n

Mixture Distributions<\/b><\/span><\/p>\n

Mixture distributions are used to model individual heterogeneity of capture probabilities (<\/span>Pledger 2000<\/a><\/span>, <\/span>Norris and Pollock 1996<\/a><\/span>) in the closed captures<\/a> data type.\u00a0 To change the number of mixture distributions, you have to change data type<\/a>, available under the PIM menu choice. Mixture models have also been added for the occupancy data type<\/a>, and the robust design occupancy data types<\/a>.\u00a0 In addition, <\/span>mixture models for open populations<\/a><\/span> are available for the Cormack-Jolly-Seber data type, the <\/span>Pradel data type<\/a><\/span>, the <\/span>Link-Barker<\/a><\/span> data type, and the Seber parameterization of dead recoveries data type (only the survival rate is included in the mixtures, <\/span>Pledger and Schwarz 2002<\/a><\/span>)..<\/span><\/p>\n

Mixture models consist of a pi parameter that gives the probability of a mixture, with the sum of the pi values equaling 1.\u00a0 In MARK, 1 less pi value is included in the model, so that the last pi value is obtained by substraction.\u00a0 When you specify >2 mixtures, the multinomial logit link function (mlogit link function)<\/a> on pi is useful to maintain this constraint.<\/span><\/p>\n

The PIM for the parameter that is being modeled as a mixture has separate rows for each mixture.\u00a0 So, as an example, for the <\/span>Pradel<\/a><\/span> mixture model<\/a><\/span>, the p<\/i> parameter is modeled as a mixture.\u00a0 Each row of the p PIM corresponds to a mixture.\u00a0 With 2 mixtures, there are 2 rows of p parameters.\u00a0 The same structure is used for the <\/span>closed capture models<\/a><\/span> with <\/span>mixtures<\/a><\/span>.<\/span><\/p>\n

Mixture models can have multiple modes, so care with their optimization should be taken.\u00a0 The simulated annealing algorithm<\/a> included in MARK is a good method to avoid local maxima.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Contents – Index Mixture Distributions Mixture distributions are used to model individual heterogeneity of capture probabilities (Pledger 2000, Norris and Pollock 1996) in the closed captures data type.\u00a0 To change the number of mixture distributions, you have to change data …<\/p>\n

Mixture Distributions<\/span> Read More »<\/a><\/p>\n","protected":false},"author":117,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-339","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/pages\/339","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/users\/117"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/comments?post=339"}],"version-history":[{"count":1,"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/pages\/339\/revisions"}],"predecessor-version":[{"id":340,"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/pages\/339\/revisions\/340"}],"wp:attachment":[{"href":"https:\/\/sites.warnercnr.colostate.edu\/gwhite\/wp-json\/wp\/v2\/media?parent=339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}