Statistics Ch 4

  1. Scatterplots
    One axis represents each variable, data plotted as points
  2. Response /Dependent variable
    measures or records the outcome (y-axis)
  3. Explanatory /Independent variable
    explains changes in the response variable (x-axis)
  4. Form
    linear, non-linear, no relationship, curved, clustered
  5. Direction
    positive, negative, no direction
  6. Strength
    how much scatter around the main form
  7. Outliers
    deviations from the main pattern
  8. Correlation
    • Correlation coefficient (r) - a measure of the direction and strength of a relationship. It is
    • calculated using the mean and the standard deviation of both the x and y variables.
    • Image Upload 1

    • r ranges from -1 to +1
    • When variability in one or both variables decreases, the correlation coefficient gets
    • stronger (closer to +1 or −1).
    • Correlations are calculated using means and standard deviations and thus are NOT
    • resistant to outliers.
Card Set
Statistics Ch 4
Scatterplots and Correlation Relationship between two variables