STATISTICS

1
STATISTICS

• Statistics refers to a set of techniques that are
  used to transform raw data into useful information

2
Three Terms Describe Statistics

• Descriptive Statistics or Data Description
• Probability and
• Inference

3
Descriptive Statistics

• Involves computing summary measures and
  constructing graphs, tables and charts to
  illustrate those measures

4
Probability

• Involves the measurement of the uncertainty that
  the decision maker feels about the occurrence of
  some outcome

5
Inference

• Involves drawing conclusions about a large body
  of data when only a small portion of those data
  has actually been observed

6
Statistical Decision-Making Process

• Decision Problem
• Statistical Plan
• Data Description and Summary
• Analysis and Conclusions
• Testing Validity of Results
• If Yes, Solution to Decision Problem
• If No, Revise the Statistical Plan

7
A Statistical Plan Includes

• Identification of a Data Base
• Techniques for Describing the Data
• A Means of Analyzing the Data and
• Measures of Validity (Error) in Working with the
  Data

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Data Base

• Primary Data
• Data collected by observation, experiment,
  simulation or from surveys

• Secondary Data
• Data published by governmental, industrial or
  individual sources

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Methods of Obtaining Data

• Observation
• Personal Interview
• Telephone Interview and
• Mail Questionnaires

10
Data Levels

• Nominal, where numbers or symbols are used to
  describe an item or characteristic
• Ordinal, where decision makers rank-order the
  observations
• Interval, where the measurement of the distance
  between two data items is allowed
• Ratio, where the data have a unique or zero point