Looking at Data
There are two components in looking at or describing data:
are objects described by a set of data.
A unit can be a
person, a place, or a thing (ie.
a student, the city of West Lafayette, Purdue
is any characteristic of an individual.
For you, a Purdue college
student, it could be your birth date, sex, marital status, major, …….
There are two types of variables:
, takes numerical values for which arithmetic
operations such as adding and averaging make sense.
An example for you,
as Purdue students, would be your age, your GPA, your numeric total score
for this course.
, places an individual into one of several groups or
categories, uses the count or percent of the individuals for each category.
An example for you, as Purdue students, would be your Major, gender
(Male/Female), your academic year (Fresh, Soph, Junior, Senior/Super-
Senior, or 1
, or 4
The distribution of a variable
describes what values that variable takes and
how often it takes on that value.
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.