III. Summarizing Distributions
Prerequisites
none
 Central Tendency
 What is Central
Tendency
 Measures of Central
Tendency
 Balance Scale Simulation
 Absolute Difference
Simulation
 Squared Differences
Simulation
 Median and Mean
 Mean and
Median Simulation
 Additional
Measures
 Comparing
measures
 Variability
 Measures of
Variability
 Variability Demo
 Estimating
Variance Simulation
 Shape
 Comparing
Distributions Demo
 Effects of Transformations
 Variance Sum
Law I
 Exercises
 PDF Files (in
.zip archive)
Descriptive statistics often involves using a
few numbers to summarize a distribution. One important aspect
of a distribution is where its center is located. Measures
of central tendency are discussed first.
A second aspect of a distribution is how spread out it is. In
other words, how much the numbers in the distribution vary from
one another. The second section describes measures
of variability. Distributions can differ in shape. Some distributions
are symmetric whereas others have long tails in just one direction.
The third section describes measures of the shape of distributions.
The final two sections concern (1) how transformations
affect measures summarizing distributions and (2) the variance
sum law,
an important relationship involving a measure of variability.
