Chapter 1: Looking at Data - Distributions
Readings: Sections 1.1, 1.2
September 1, 2009
: objects being described by a set of data (people, households, cars, animals, corn,
: characteristics of individuals (height, yield, length, age, eye color, etc.)
: places an individual into one of several groups (gender, eye color, college major,
: attaches a numerical value to a variable so that adding or averaging the values
makes sense (height, weight, age, income, yield, etc.)
Distribution of a variable
: describes what values that variable takes and how often it takes on
If you have more than one variable in a problem, look at each variable by itself ﬁrst, then look
for any relationships between the variables.
: Identify whether the following questions would give you categorical or quantitative
data. If it is categorical, state the possible answers.
a. What letter grade did you get in your Calculus class last semester?
b. What was your score on the last exam?
c. What is your GPA?
d. Did you vote for Barack Obama?
e. How many votes did George W. Bush get?
Visual display of data
Example 2 (
Messy room example
: In a poll of 200 parents of children ages 6 to 12, respondents were
asked to name the most disgusting things ever found in their children’s rooms. The results are below
Most disgusting thing
# of parents
% of parents
Animal and insect-related nuisances
Clothing (dirty socks and underwear especially)