Introduction to Statistics
Chapter 1
§ 1.2
Data Classification
Larson & Farber, Elementary Statistics: Picturing the World, 3e 3
Types of Data
Data sets can consist of two types of data: qualitative data
and quantitative data.
Data
Qualitative
Data
Quantitative
Data
Consists of
attributes, labels,
or nonnumerical
entries.
Consists of
numerical
measurements or
counts.
Larson & Farber, Elementary Statistics: Picturing the World, 3e 4
Qualitative and Quantitative Data
Example:
The grade point averages of five students are listed in the
table. Which data are qualitative data and which are
quantitative data?
Student GPA
Sally 3.22
Bob 3.98
Cindy 2.75
Mark 2.24
Kathy 3.84
Quantitative dataQualitative data
Larson & Farber, Elementary Statistics: Picturing the World, 3e 5
Levels of Measurement
The level of measurement determines which statistical
calculations are meaningful. The four levels of
measurement are: nominal, ordinal, interval, and ratio.
Levels
of
Measurement
Nominal
Ordinal
Interval
Ratio
Lowest
to
highest
Larson & Farber, Elementary Statistics: Picturing the World, 3e 6
Nominal Level of Measurement
Data at the nominal level of measurement are qualitative
only.
Levels
of
Measurement
Nominal
Calculated using names, labels,
or qualities. No mathematical
computations can be made at
this level.
Colors in
the US
flag
Names of
students in your
class
Textbooks you
are using this
semester
Larson & Farber, Elementary Statistics: Picturing the World, 3e 7
Ordinal Level of Measurement
Data at the ordinal level of measurement are qualitative
or quantitative.
Levels
of
Measurement Arranged in order, but
differences between data
entries are not meaningful.
Class standings:
freshman,
sophomore,
junior, senior
Numbers on the
back of each
player’s shirt
Ordinal
Top 50 songs
played on the
radio
Larson & Farber, Elementary Statistics: Picturing the World, 3e 8
Interval Level of Measurement
Data at the interval level of measurement are quantitative.
A zero entry simply represents a position on a scale; the
entry is not an inherent zero.
Levels
of
Measurement
Arranged in order, the differences
between data entries can be calculated.
Temperatures Years on a
timeline
Interval
Atlanta Braves
World Series
victories
Larson & Farber, Elementary Statistics: Picturing the World, 3e 9
Ratio Level of Measurement
Data at the ratio level of measurement are similar to the
interval level, but a zero entry is meaningful.
Levels
of
Measurement
A ratio of two data values can be
formed so one data value can be
expressed as a ratio.
Ages Grade point
averages
Ratio
Weights
Larson & Farber, Elementary Statistics: Picturing the World, 3e 10
Summary of Levels of Measurement
NoNoNoYesNominal
NoNoYesYesOrdinal
NoYesYesYesInterval
YesYesYesYesRatio
Determine if
one data value
is a multiple of
another
Subtract
data values
Arrange
data in
order
Put data
in
categories
Level of
measurement

Type of data

  • 1.
  • 2.
  • 3.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 3 Types of Data Data sets can consist of two types of data: qualitative data and quantitative data. Data Qualitative Data Quantitative Data Consists of attributes, labels, or nonnumerical entries. Consists of numerical measurements or counts.
  • 4.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 4 Qualitative and Quantitative Data Example: The grade point averages of five students are listed in the table. Which data are qualitative data and which are quantitative data? Student GPA Sally 3.22 Bob 3.98 Cindy 2.75 Mark 2.24 Kathy 3.84 Quantitative dataQualitative data
  • 5.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 5 Levels of Measurement The level of measurement determines which statistical calculations are meaningful. The four levels of measurement are: nominal, ordinal, interval, and ratio. Levels of Measurement Nominal Ordinal Interval Ratio Lowest to highest
  • 6.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 6 Nominal Level of Measurement Data at the nominal level of measurement are qualitative only. Levels of Measurement Nominal Calculated using names, labels, or qualities. No mathematical computations can be made at this level. Colors in the US flag Names of students in your class Textbooks you are using this semester
  • 7.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 7 Ordinal Level of Measurement Data at the ordinal level of measurement are qualitative or quantitative. Levels of Measurement Arranged in order, but differences between data entries are not meaningful. Class standings: freshman, sophomore, junior, senior Numbers on the back of each player’s shirt Ordinal Top 50 songs played on the radio
  • 8.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 8 Interval Level of Measurement Data at the interval level of measurement are quantitative. A zero entry simply represents a position on a scale; the entry is not an inherent zero. Levels of Measurement Arranged in order, the differences between data entries can be calculated. Temperatures Years on a timeline Interval Atlanta Braves World Series victories
  • 9.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 9 Ratio Level of Measurement Data at the ratio level of measurement are similar to the interval level, but a zero entry is meaningful. Levels of Measurement A ratio of two data values can be formed so one data value can be expressed as a ratio. Ages Grade point averages Ratio Weights
  • 10.
    Larson & Farber,Elementary Statistics: Picturing the World, 3e 10 Summary of Levels of Measurement NoNoNoYesNominal NoNoYesYesOrdinal NoYesYesYesInterval YesYesYesYesRatio Determine if one data value is a multiple of another Subtract data values Arrange data in order Put data in categories Level of measurement