Upper Midwest Environmental Sciences Center
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Long
Term Resource Monitoring Program
Estimating
power to detect temporal trends in LTRMP metrics
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Disclaimer: This information is provided to help better inform ongoing LTRMP partner discussions. The power plots are generated from small sample sizes; all plots should be treated as approximate. Contact: Questions or comments may be directed
to Brian Gray, LTRMP statistician, Upper Midwest Environmental
Sciences Center, La Crosse, Wisconsin,
at brgray@usgs.gov. |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.umesc.usgs.gov/ltrmp/power_plots_fig3a.html
Page Contact Information: Contacting the Upper Midwest Environmental Sciences Center
Page Last Modified:
October 2, 2007
Figure 3a: Estimated power to detect temporal trends in bluegill (Lepomis macrochirus) catch-per-unit effort (CPUE) in Pool 4 in all sampled strata (backwater, main channel border, wing dam, side channel strata) under half the present sampling intensity (n ≈ 41). Trends assumed exponential. The CPUE represents mean catch per 15-min effort. Estimates based on design-based, across-episode annual means. Note that halving the present sampling intensity for day electrofishing in Pool 4, without adjusting relative sampling intensities across strata, may lead to inadequate sample sizes for some strata.
