Chapter 1 - Introduction

1
Chapter 1 - Introduction

• Math 22
• Introductory Statistics

2
What is Statistics?

• Statistics - Involves the collection,
  organization, interpretation, and presentation of
  numerical information.

3
Introductory Terms

• Experimental Units - Subjects
• Variable A characteristic of interest about
  each individual element of a population or sample
• Observations Particular information that we
  collect from each subject.
• Data Set Collection of observations.

4
Items That We Might Want to Study

• Population - Collection of all objects or items
  that are of interest in a statistical study.
• Sample - A finite portion (subset) of the
  population that is used to study the
  characteristics of concern in the population.
• Target Population - Population of interest in the
  study.

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Items That We Might Want to Study

• Parameter A numerical value summarizing the
  entire population
• Sample Statistic A numerical value summarizing
  the sample data.
• Census - A sample consisting of the entire
  population. (An attempt to sample the entire
  population)

6
Descriptive and Inferential Statistics

• Descriptive Statistics - Describes the state of
  the data which has been collected.
• Inferential Statistics - Generalizations or
  conclusions that extend beyond the collected
  data, what we call the population.

7
Levels of Measurement

• Nominal Scale
• Variables that categorize without any form of
  natural ordering.
• Ordinal Scale
• Variables that categorize with a form of natural
  ordering
• Interval Scale
• Require a physical unit of measure. There is no
  absolute zero (starting point).

8
Levels of Measurement

• Ratio Scale
• Very similar to interval scale variables. The
  key difference is that ratio scale variables have
  an absolute starting point, an absolute zero.

9
Types of Measurements

• Numerical Variable (quantitative variable) -
• A variable whose values are numbers obtained by
  a measurement.
• Discrete Variable
• Continuous Variable

10
Types of Measurements

• Categorical Variable (Qualitative Variable) -
• Variable whose values are classifications or
  categories. (i.e. Coding)