OT 667

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OT 667

• Judging Studies

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http//www.fhs.mcmaster.ca/canchild/publications/o
utcome_measures.html
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Why do we measure things?
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In order to

• Describe
• Compare
• Categorize levels of function
• Document improvement
• Demonstrate efficacy

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One way to manipulate numbers

• Statistics (measures of a sample) or
• Parameters (measures of a population) can
• be used to organize, summarize and
• analyze measurements to give information

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Levels of Measurement

• Nominal categorical variables (gender, hair
  color, ethnicity)
• Ordinal rank order of observation (muscle
  testing, pain levels, military rank)
• Interval equal intervals between scores but no
  true zero (calendar years, degrees centigrade or
  Fahrenheit
• Ratio true equal intervals between units,
  measured from true zero (distance, age, time,
  weight, strength, blood pressure)

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Kinds of Statistics

• Descriptive statistics the use of measures to
  describe aspects of a sample or population
• Inferential statistics the process of drawing
  inferences/making judgments about samples that
  are generalized to the larger population

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Descriptive Statistics

• Measures of central tendency
• Measures of variability
• Relationship to the normal curve

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Measures of Central Tendency

• Mode - the most frequently occurring score in a
  distribution
• Median the exact middle score in a distribution
• Mean the average score of a distribution

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Levels of Measurement and Measures of Central
Tendency

• Mode Median Mean
• Nominal Ordinal Interval
• Ordinal Interval Ratio
• Interval Ratio
• Ratio

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Measures of Variability

• Range the difference between the highest and
  lowest scores in a distribution
• Variance the mean of the square deviation
  scores
• Standard Deviation the square root of the
  variance most consistently used variation score