Chapter 2: Data

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Chapter 2 Data

• We did not have data at the beginning of our
  business, but find it invaluable now. We have
  history now, so we can make predictions and
  projections in a much more intelligent and
  reasonable manner.
• Amber Chand
• President for Vision, Eziba

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What Are Data?

• Data are values along with their context.
• Context
• Who
• What
• When
• Where
• Why
• How

• Context becomes clear when the values are
  organized in data tables.
• Who rows
• What columns

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Who

• Each row of a data table corresponds to an
  individual about whom we record some
  characteristics.
• Individuals are given different names based upon
  the situation
• Repondents (survey)
• Subjects (experiment)
• Participants (experiment)
• Experimental units (experiment)
• Records (business)
• Cases (generic term)

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What

• Variables
• The characteristics recorded about each
  individual.
• Shown in the columns of the data table.
• Categorical data
• Represent categories of the variables.
• Ex gender, race, religion, etc.
• Quantitative data
• Variables recorded in numbers.
• Variables that have measurement units that tell
  how a quantitative value has been measured.
• Ex income, height, weight, age, etc.

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When, Where, How, and Why

• When and Where may provide insight into the
  recorded values
• How the data is collected is extraordinarily
  important!
• Why the data is collected provides insight
• Knowing Why data were collected may show problems
  in How the data were measured or observed
• Knowing Why data were collected may show problems
  in the decision-making process about the Who and
  What of the data.

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What Can Go Wrong?

• Dont assume that because a variables values are
  numbers you are working with quantitative data.
• Categories are often given numeric labels.
• Look at the context.
• Always be skeptical.
• Context colors the interpretation of data.

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TI-84 Tips

• To enter data
• STAT EDIT
• L1, L2, ETC.
• To change an entry
• Use arrows to highlight entry
• Type in new value or DEL to delete entry.
• To add an entry
• 2nd INS
• Enter the new value
• If you delete a list
• STAT EDIT
• SetUp Editor