1. For which scales can a mean be calculated
    • Nominal
    • Interval
    • Ratio
  2. For which scales can a median be calculated
    • Ordinal
    • Interval
    • Ratio
  3. For which scales can a mode be calculated?
    • Nominal
    • Ordinal
    • Interval
    • Ratio
  4. Advantages & Disadvantages of using the mean
    • easily manipulated algebraically
    • reliable because it takes into account every measure of a data set

    greatly affected by extreme scores
  5. Advantages & Disadvantages of Median
    • little influence by extreme scores
    • reasonable estimate of the center of a distribution

    may not be good to ignore extreme values
  6. Advantages & Disadvantages of Mode
    not influenced by extreme scores

    • may not represent the scores
    • ignores extreme values completely
  7. How to calculate IQR?
    • Find the median location (n+1)/2
    • Find quartile location (ML+1)/2
    • Find Q1 & Q3 (low score + QL; high - QL)
    • IQR= distance btwn Q3 - Q1
    • Outliers: Q3+ (1.5 x IQR); Q1-(1.5 x IQR)
  8. Empirical Rule...
    68-95-99.7 within 3 standard deviations of the mean
  9. Deviation
    the difference btwn each score and the mean of the data set
  10. Variance
    single number representing the average amount of variation in a data set
  11. Standard deviation
    Measure of the spread of scores out from the mean of the sample
Card Set