hvad gør man her?
June 11th, 2007 by Skipper
Hej Laura
Her kan du putte dine breve og andre publikationer. Dine venner kan også skrive til dig her.
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Archive for June, 2007
Hvad kan du så her
June 11th, 2007 by Skipper
Hej Jonas
Her kan du putte dine breve og andre publikationer. Dine venner kan også skrive til dig her.
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Hvad kan du
June 11th, 2007 by Skipper
Hej Anna
Her kan du putte dine breve og andre publikationer. Dine venner kan også skrive til dig her.
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Forberedelse
June 11th, 2007 by Skipper
Methods providing a more coherent statistical treatment of survey data including zeroes have been described. The Delta approach includes two separate models, one for occurrence (zeroes and non-zeroes) and another for abundance at sites with positive catch: the delta lognormal- or the delta gamma model (Pennington 1983, 1996; Myers & Pepin 1990)) and GLM within the delta approach (Stefánsson 1996). Combining the delta and GLM approach has the following advantages: by analysing the entire time series and not just one year at a time as in standard approaches, the spatial pattern of stock density can be modelled by including area variables. Other structuring variables (e.g. environmental variables) may also be added to further account for parts of the residual (other than year effect) variation. Under the GLM structure missing data—typically originating from incomplete surveys—can be accommodated.
