Data Quality Assessment
for Environmental
Decision Making
Course Description
The Data Quality Assessment
(DQA) process seeks to determine whether the type, quantity, and quality
of environmental data needed to support a decision has been achieved.
This course will introduce environmental professionals to this approach
using a combination of lectures, hands-on exercises, and computer simulations
tied to the exercises. Students taking this class will experience data
quality assessment by analyzing data collected by the class. Some of
this data will be collected from simulated populations with known properties
and some will be data collected with field instrumentation.
The motto of this class is,
"The best way to learn is to do." Therefore, the student can
expect to gain practical experience in the basics of data analysis in
a non-threatening, friendly environment. This class is designed to be
a pleasant experience-one where everything possible is done to visually
and manually illustrate new statistical concepts.
The DQA process is made up
of the following five steps:
- Review DQOs and the Sampling
Design
- Conduct a Preliminary
Data Review
- Select the Statistical
Test
- Verify the Assumptions
- Draw Conclusions from
the Data
These five steps will be
addressed in the following manner:
- The class will briefly review the DQO process, but it is assumed
that the student has had previous experience or training in DQOs.
- The class will learn the meaning and use of numerical summaries
that enable the analyst to estimate a central tendency in the data,
the variability of the data, and other statistical quantities.
The class will learn how well chosen graphs can be a powerful tool
to see nuggets of important information in a sea of numbers.
- The class will discuss several common statistical hypothesis tests
and give students opportunity to view visual simulations that illustrate
important principles that underlie these tests.
- The assumptions and limitations of a variety of tests will be discussed
and illustrated.
- Students will get a chance to draw conclusions from their sample
data and compare the results with the true population parameters.
The textbook for the class
is Guidance for Data Quality Assessment Practical Methods for Data Analysis
EPA QA/G-9. The latest version of this document is available for free
download as a PDF file from the following web site:
http://www.epa.gov/quality1/qa_docs.html
Each student should have their own copy of this document. Some of the
examples and data in QA/G-9 will be used for class exercises.
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