Data

• correlation does not equal causation

  • correlation: similarities, patterns

  • causation: this thing caused that thing

• Metadata

  • data that describes other data

    • digital image may include metadata that describes the size of the image, number of colors, and creation date

Filtering and Cleaning Data

• cleaning data

  • process that makes the data uniform without changing its meaning

    • needs to be done when:

      • data is incomplete

      • data is invalid

      • multiple tables are combined into one

    • What leads to “messy” data?

      • users enter in different types of data (“two”, 2)

      • users use different abbreviations to represent the same info

      • data may have different spellings or inconsistent capitalization

• filtering data allows the user to look at.a subset of the data

Exploring Two Columns

• Crosstab chart

  • counts how many times combinations of values appear. Arrows show where that row in the data table would be counted in the chart

  • useful for:

    • finding the most/least common combinations of values in two columns

    • finding patterns across two columns

    • exploring two columns when one or both are strings

  • Not useful:

    • if either column has too many values

• Scatter

  • show combinations of values from two columns

    • useful for:

      • seeing patterns and trends between two balues

      • numeric data with lots of different values

    • not useful:

      • lots of repeated values

Big, Open, and Crowdsourced Data

• big data

  • a broad term for datasets os large or complex that traditional data processing applications are inadequate

• citizen science

  • scientific research conducted in whole or part by distributed individuals (not always scientists) who contribute relevant data to research using their own computing devices

• crowdsourcing

  • the practice of obtaining input or information from a large number of people via the internet

• Open data

  • data that can be freely used, re-used and redistributed by anyone

Machine Learning

“How do machines learn?”

• Machine Learning

  • an application of artificial intelligence that provides systems the ability to automatically learn and improve from experience without being explicitly programmed

• data bias

  • data that does not accurately reflect the full population or phenomenon being studied