Chapter 1 Section 1

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Chapter 1Section 1

• Introduction to the
• Practice of Statistics

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Chapter 1 Section 1

• The science of statistics is
• Collecting
• Organizing
• Summarizing
• Analyzing
• information to draw conclusions or answer
  questions

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Chapter 1 Section 1

• Anecdotal claims, as opposed to statistics, are
• Conclusions based on very little data
• Stories and rumors

• Anecdotal claims, as opposed to statistics, are
• Conclusions based on very little data
• Stories and rumors
• Data can be misused when
• Data is incorrectly obtained
• Data is incorrectly analyzed

• Anecdotal claims, as opposed to statistics, are
• Conclusions based on very little data
• Stories and rumors
• Data can be misused when
• Data is incorrectly obtained
• Data is incorrectly analyzed
• Good statistics should
• Understand the difference between direct and
  indirect (lurking variable) relations
• Understand the impacts of variability

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Chapter 1 Section 1

• Statisticians Creed In God We Trust.all
  others, bring data!
• G.I.G.O. Garbage In, Garbage Out!
• Our text talks about design of a data collection
  method early to emphasize the importance!

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Chapter 1 Section 1

• A population
• Is the group to be studied
• Includes all of the individuals in the group

• A population
• Is the group to be studied
• Includes all of the individuals in the group
• A sample
• Is a subset of the population
• Is often used in analyses because getting access
  to the entire population is impractical

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Chapter 1 Section 1

• Organize and summarize the information
• Descriptive statistics (chapters 2 through 4)
• Visual methods such as charts and graphs
• Numeric methods such as calculations

• Organize and summarize the information
• Descriptive statistics (chapters 2 through 4)
• Visual methods such as charts and graphs
• Numeric methods such as calculations
• Draw conclusions from the information
• Inferential statistics (chapters 8 through 15)
• Various methods that are appropriate for
  different questions and different types of data
  sets

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Chapter 1 Section 1

• Characteristics of the individuals under study
  are called variables
• Some variables have values that are attributes or
  characteristics those are called qualitative or
  categorical variables
• Some variables have values that are numeric
  measurements those are called quantitative
  variables
• The suggested approaches to analyzing problems
  vary by the type of variable

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Chapter 1 Section 1

• Examples of qualitative variables
• Gender
• Zip code
• Blood type
• States in the United States
• Brands of televisions
• Qualitative variables have category values
  those values cannot be added, subtracted, etc.

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• Examples of quantitative variables
• Temperature
• Height and weight
• Sales of a product
• Number of children in a family
• Points achieved playing a video game
• Quantitative variables have numeric values
  those values can be added, subtracted, etc.

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Chapter 1 Section 1

• Quantitative variables can be either discrete or
  continuous

• Quantitative variables can be either discrete or
  continuous
• Discrete variables
• Variables that have a finite or a countable
  number of possibilities
• Frequently variables that are counts

• Quantitative variables can be either discrete or
  continuous
• Discrete variables
• Variables that have a finite or a countable
  number of possibilities
• Frequently variables that are counts
• Continuous variables
• Variables that have an infinite but not countable
  number of possibilities usually ranging over
  interval
• Frequently variables that are physical
  measurements

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Chapter 1 Section 1

• Examples of discrete variables
• The number of heads obtained in 5 coin flips
• The number of cars arriving at a McDonalds
  between 1200 and 100
• The number of students in class
• The number of points scored in a football game
• How many typos there are in this presentation

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Chapter 1 Section 1

• Examples of continuous variables
• The distance that a particular model car can
  drive on a full tank of gas
• Heights of college students
• Density of a liquid
• Mass of a textbook

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Summary Chapter 1 Section 1

• The process of statistics is designed to collect
  and analyze data to reach conclusions
• Variables can be classified by their type of data
• Qualitative or categorical variables
• Discrete quantitative variables
• Continuous quantitative variables