1. Mean
    1. Sensitive to the exact value of all scores in the distribution
    2. Sum of deviations about the mean equals zero
    3. Sensitivity to Extreme Scores
    4. Sum of squared deviations of all scores about the mean is a minimum
    5. Sensitivity to Sampling Variation
    6. Can figure out overall mean if have mean and n of subgroups
  2. Median
    1. Value below which 50% of the scores fall - P50
      1. Centermost score if odd number of scores
      2. Average of centermost scores if even number of scores
    2. Sensitivity to Extreme Scores
    3. Sensitivity to Sampling Variation
  3. Mode
    1. Most frequent
    2. Unimodal vs. bi-modal
  4. Central Tendency and Symmetry
    1. Unimodal and symmetrical -
    2. Skewed -
  5. Variability -
    1. Logic
      1. Range -
      2. Deviation -
      3. What if add deviations?
      4. What else could you do? What if square the deviations?
      5. How useful is the sum of squares?
      6. How useful is the variance?
      7. Variance is useful later on.
    2. Alternative Formula -
    3. Properties of SD
      1. Measure of dispersion relative to the mean
      2. Sensitive to each score in the distribution
      3. Stable with regard to sampling fluctuations
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