Principles of Vegetation Measurement & Assessment
and Ecological Monitoring & Analysis


Veg Sampling
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Data and Distributions

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Readings & Instructions

  1. Read through pages 66-70 in Chapter 5 of Measuring and Monitoring Plant Communities.
  2. Read text below and visited recommended sites.
  3. Work through Summary Questions at the end of the text.

What this Reading Covers

Data & Distributions

To speak effectively about vegetation measurements one must "know the language."  Many of the following terms probably have some meaning to you, but do you know the precise, statistical meaning of these words?

  • Attribute

  • Population

  • Sample

  • Parameter

  • Statistic

  • Sampling Distributions

  • Sample Mean

  • Sample Variance

  • Standard Error

  • Confidence Interval

  • Accuracy and Bias

  • Precision and Error

There are several good on-line modules and pages describing these terms. Visit the following two sites to explore and discover the meaning of these words:


** Note: This course will include substantial use of descriptive statistics.  A basic statistics class was not required for the course. However, if you have not had a stats course or if you need a refresher, I suggest you visit the sites listed above and understand the terms listed above. 

Summary Questions

  1. What is the difference between a population and a sample?
  2. Why would we take a sample instead of measuring the whole population?
  3. When would it be more appropriate to calculate and report a sample median instead of a sample mean?
  4. If I measured grass height with a mean of 25 cm and a 95% confidence interval of 10 cm, what am I 95% confident in?  I am 95% confident that......

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