Statistics 300: Introduction to Probability and Statistics

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Statistics 300Introduction to Probability and
Statistics

• Section 2-2

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Chapters 2 and 3

• Describing data
• Exploring data
• Comparing data

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Describe or Infer?

• Descriptive statistics
• Inferential statistics

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Descriptive Statistics

• Describe characteristics of (statistics) data
  samples as they are without extending their
  meaning beyond the data sample
• Chapters 2 through 6

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Inferential Statistics

• Based on a sample or multiple samples, make
  inferences (judgments) about the population(s)
  from which the sample(s) came.
• Chapters 7 through 12

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Descriptive Statistics

• Distribution
• Center
• Variation
• Position

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Distribution

• How are the data spread out?
• Where are data plentiful?
• Where are data rarely found?

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Distribution

• Frequency tables
• Pictures

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Frequency Tables

• Identify categories for the data
• Nominal categories or
• Interval categories
• Count the number of observations in each category

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Frequency TablesInterval Categories

• Class Limits
• Class Midpoints
• Class Boundaries

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Class Limits

• Convenient values representing the range of
  values in a class
• Lower class limit
• Upper class limit

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Class Midpoints

• Values that are midway between the lower and
  upper class limits of each class
• To compute, average the two class limits

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Class Boundaries

• Values that truly separate one class from the
  next
• To compute average the upper class boundary and
  the following lower class boundary

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Frequency Tables

• Frequency
• Relative frequency
• Cumulative frequency
• Cumulative relative frequency

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Frequency

• Count of the observations that belong to each
  class

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Relative Frequency

• Frequency divided by the total number of
  observations

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Cumulative Frequency

• Sum of the frequencies in the first class through
  the current class

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Cumulative Relative Frequency

• Sum of the relative frequencies in the first
  class through the current class

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Distribution

• Frequency tables
• Pictures

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Pictures

• Histograms and Bar Charts
• Pareto Charts
• Pie Charts