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I'm a rookie in statistics, but just wrapped up a semester of R analysis for natural resources. I'm working on my grad capstone and hoping I might be able to get some help generating ideas for worthwhile analysis to answer the following questions:

****Changes in Run Timing**** I don't have any effect for this question, but just wanting to show how the timing of the fish run has changed from the start of a project to current times. My data is based off of trapping. I was thinking of determining the peak annually, then doing an ANOVA or Linear Model. Is there a better way of doing this?

****Changes in fork lengths**** I have fork length data for multiple rivers over a 15 year period. I wanted to analyze how hatchery or wild status predicts lengths. Are hatchery fish smaller/longer than wild? I had thought to find the mean fork length for fish annually both by sex and hatchery/wild status, then do ANOVA or Linear Model. Is there a better way of analyzing?

****Changes in Age Structure**** Through field sampling, I have scale analysis results telling me the age structure of each year's spawners. Similar to fork lengths, how has this changed over time, and specifically, as an effect of wild/hatchery status and sex.

Any help is much appreciated! Just looking for some ideas because while I really enjoyed ANOVA/regression analysis, I'm sure there are some much better ideas for these questions.

Thanks!

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  • $\begingroup$ Are you interereted in Anova or regression ? $\endgroup$ Jun 19 '17 at 12:21
  • $\begingroup$ Either or, just trying to figure out which analysis would make the most sense in this case. $\endgroup$
    – salmon_man
    Jun 20 '17 at 4:05
  • $\begingroup$ One-way Anova should be a good option for your issues - fork length and age-structure presuming that you are not interested in a single complete model. $\endgroup$ Jun 20 '17 at 5:28
  • $\begingroup$ Thank you. A 1-way ANOVA makes sense for those. I was also contemplating a 3-way ANOVA to look at what is a better predictor on fork length - sex, mark status, or age. $\endgroup$
    – salmon_man
    Jun 21 '17 at 1:23
  • $\begingroup$ what is matk status ? $\endgroup$ Jun 21 '17 at 5:39
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In view of your comments(following your question), you can apply ANOVA to find out the effect of mark-up(hatchery Versus wild) and sex-type (male Vs. female) on fork-length. And two-way Anova could be implemented for evaluating the combined-effect of the specified variables i.e whether mark-up and sex-type together affect the fork-length significantly. Two way Anova will account for interactions. Given the nature of two variables - Age and fork-length, these may be analyzed by correlation-analysis and/or regression analysis. The combined effect of all three variables may be estimated and tested with the help of lme - Linear mixed-effect model.

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  • $\begingroup$ Great, thank you! Lastly, to compare the mean return peaks from each year, what would be best way to do so? I'd have 15 years. $\endgroup$
    – salmon_man
    Jun 24 '17 at 5:11
  • $\begingroup$ mean return peaks - data ? annual ? for different categories or meta-analytic i.e. over $\endgroup$ Jun 24 '17 at 11:52
  • $\begingroup$ not clear. please explain - what is mean return peak? For what do you want to estimate - category-wise , sexwise , etc. $\endgroup$ Jun 24 '17 at 11:58
  • $\begingroup$ Please elaborate the mean return peaks and what is your data ? $\endgroup$ Jun 24 '17 at 12:09
  • $\begingroup$ I have dates with numbers of fish that returned each day for that year. I was going to convert this to Days after Trapping Began. So one year, my average peak might be 35 days, another year 30, and so forth. Thank you! $\endgroup$
    – salmon_man
    Jun 24 '17 at 23:55

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