levels of measurement

• What is the purpose of levels of measurement in psychology?

  To decide what data to record and measure
• What types of data might psychologists record?

  Raw data, rating scales, precise measurements
• What are the three types of data discussed in the video?

  Nominal, ordinal, and interval data
• What is nominal data?

  • Data referring to categories
  • Also called categorical data
  • Example: pet ownership frequency
• How is nominal data exemplified in pet ownership?

  By counting the number of pets in categories
• Can we compare differences between categories in nominal data?

  No, categories do not interact meaningfully
• What is ordinal data?

  • Data that can be ordered
  • Differences between points are not equal
  • Examples: race positions, height, happiness scales
• What does ordinal data allow us to do?

  Place data points in order
• What is a key limitation of ordinal data?

  Differences between points are subjective
• What is interval data?

  • Data with equal units of measurement
  • Examples: length, speed, age, temperature
  • Allows for precise comparisons
• How does interval data differ from nominal and ordinal data?

  It has equal intervals between points
• What is ratio data?

  Interval data with an absolute zero point
• Why is temperature in degrees Celsius considered interval data?

  It can have negative values
• How can nominal, ordinal, and interval data describe a race?

  • Nominal: Competitors' countries of origin
  • Ordinal: Order of finishers
  • Interval: Time differences between runners
• What does nominal data tell us about race competitors?

  Number of competitors from each country
• What does ordinal data reveal about race results?

  Order in which runners finished the race
• What does interval data provide in the context of a race?

  Precise time differences between runners
• How can you convert between levels of measurement?

  • Interval to ordinal: Rank scores
  • Ordinal to nominal: Create categories
• Can you convert from ordinal to interval data?

  No, only from interval to ordinal
• How do you convert ordinal data to nominal data?

  Create separate categories for rankings