Sample Frame Example

 SampleDesign4  Example AIM Project Frame and Sample Frame

  • 2 strata: Forest and Shrubland
  • 10 Plots in FOREST and 15 plots in SHRUBLAND
  • Plots are ordered within strata and between.  The order that is important is the within strata.
SampleDesign_1 The crew decided to start furthest from the Field office and work their way closer to the office.

  • Sampled 15 out of the 25 plots
  • Original Proportion of plots was 10 Plots in FOREST and 15 plots in SHRUBLAND
SampleDesign2
  • New Proportion of plots is 9 plots in FOREST and 6 plots in SHRUBLAND
  • Because plots are aggregated in one area of the Field Office, even if they are able to sample the other section of the field office next season, varying rainfall may bias the results in one geographic region over another (i.e. this field season was very rainy and next year was dry – results will imply the northwest section of the FO is in worse shape than the south east!)
SampleDesign3
    If the crew went in order (i.e. HOW YOU SHOULD SAMPLE!):
    • Sampled 15 out of the 25 plots
    • Balanced plot sampling between strata and went in order within strata.
    • Originally 10 in FOREST and 15 in SHRUBLAND; after field season the spread is 6 plots in FOREST and 9 plots in SHRUBLAND (same proportion of total plots sampled – 40% and 60%).

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