Data Example from Dixon and Massey
Note: The 'dixonmassey' data set is from Dixon WJ and Massey F Jr., Introduction to Statistical Analysis,, Fourth Edition, McGraw Hill Book Company, 1983.
Sample Size = 20 males
Examples of Descriptive Statistics
Graphical Summaries - Continuous Variables
Example: chol52
Continuous Variables
Median:
Mean:
Range:
Lower Quartile:
Upper Quartile:
Interquartile Range:
Variance:
Standard Deviation:
Categorical Variables
Counting: 7 subjects had a coronary event by 1962.
Proportions: 7/20 = 35% of patients had a coronary event by 1962.
Associations Between Pairs of Variables
Continuous and Categorical Variables
Mean of Chol52
For cor = 0, 301.85
For cor = 1, 328.43
Two Continuous Variables: Chol52 and Age
Correlation: r = -0.11
Regression: Chol52 = 341 – 0.66*age.
Two Categorical Variables:
cor and Agelt50
