Types of Variables
*Do Survey
Warm-up: Survey

Complete the survey…..we will use this
data later!
Individuals
The individuals are the objects described
by a set of data.
*Individuals may be people, animals, or
things.
*It’s the who or what that we are
studying.
Variable

It is any characteristic of an individual.

It can take different values for different
individuals.
 Example:
High school’s student data base.
New Data Set…Questions to ask
yourself.

Who are the individuals described by the
data?

How many individuals are there?

What are the variables?

In what units is each variable?
Types of Variables

Categorical – also known as qualitative
 Data

from individual is placed into a category
Quantitative – also know as numerical
 Takes
numerical values and it makes sense
to find an average
Quantitative or Qualitative?
Voter’s region – (North, South, etc)
Age – (in years)
Qual
Quan
Systolic Blood pressure (mm of mercury)
Quan
Level of calcium in the blood (micrograms/ml)
Smoker – (yes or no)
Qual
Quan
www.censusatschool.com

Hundreds of thousands of students from
Australia, Canada, New Zealand, South
Africa, and the United Kingdom.

Let’s pick 10 students…
Who are the Individuals in this data set?
What variables were
measured?
Identify each as categorical or
quantitative.
In what units were the
quantitative variables
measured?
Describe the individual in the highlighted row.
Distribution

The distribution of a variable tells us what
values the variable takes and how often it
takes these values.

It represents the pattern of variation of a
variable.
Jake is a car buff who wants to find out more about
the vehicles that students at his school drive. He
gets permission to go to the student parking lot and
record some data. Later, he does some research
about each model of car on the Internet. Then he
makes a spreadsheet that includes each car’s
model, year, color, number of cylinders, gas
mileage, weight, and whether is has a navigation
system.

Who are the individuals?

What variables did he measure?
Inference

Drawing conclusions that go beyond the
data at hand.

Using a sample group to discuss the
population.
Activity – Airlines Discrimination

Each group of 4 will split into 2 to do the
activity and 4 to discuss.
Activity – How Long is a minute
Homework

Page 7 (1, 3, 5, 6, 7, 8)