Types of DataTypes of Data

Levels of MeasurementLevels of Measurement

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-2

Basic Vocabulary of StatisticsBasic Vocabulary of Statistics

VARIABLEVARIABLEA A variable variable is a characteristic of an item or is a characteristic of an item or individual.individual.

DATADATADataData are the different values associated with a are the different values associated with a variable.variable.

OPERATIONAL DEFINITIONSOPERATIONAL DEFINITIONSData values are meaningless unless their variables Data values are meaningless unless their variables have have operational definitions, operational definitions, universally universally accepted meanings that are clear to all associated accepted meanings that are clear to all associated with an analysis.with an analysis.

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-3

Population vs. SamplePopulation vs. Sample

Population Sample

Measures used to describe the population are called

parameters

Measures computed from sample data are called

statistics

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-4

Types of VariablesTypes of Variables

CategoricalCategorical (qualitative) (qualitative) variables have values that can variables have values that can only be placed into categories, only be placed into categories, such as “yes” and “no.” They such as “yes” and “no.” They are not numbers.are not numbers.

NumericalNumerical (quantitative) (quantitative) variables have values that variables have values that represent quantities. They are represent quantities. They are numbers.numbers.

Types of VariablesTypes of Variables

CategoricalCategorical (qualitative) variables have (qualitative) variables have values that can only be placed into values that can only be placed into categories.categories.

e.g. When do you buy a newspaper? M T W Th e.g. When do you buy a newspaper? M T W Th F Sa SuF Sa Su

e.g. Do you have a driving licence? Yes Noe.g. Do you have a driving licence? Yes No

NumericalNumerical (quantitative) variables are (quantitative) variables are numbers.numbers.

e.g. How many magazines do you buy a week? e.g. How many magazines do you buy a week?

e.g. How long have you had a driving licence?e.g. How long have you had a driving licence?

e.g. How tall is the building?e.g. How tall is the building?

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-6

Types of DataTypes of Data

Data

Categorical Numerical

Discrete Continuous

Examples:

Marital Status Political Party Eye Colour (Defined categories) Examples:

Number of Children Defects per hour (Counted items)

Examples:

Weight Voltage (Measured characteristics)

More Types of DataMore Types of Data

Cross Cross Sectional DataSectional Data

Data giving a Data giving a situation at one situation at one moment in timemoment in time

Time Series Time Series DataData

Gives values of Gives values of same variable same variable (measured or (measured or counted) at counted) at different points different points in timein time

More Types of DataMore Types of Data

Cross Sectional Cross Sectional DataData

Data giving a Data giving a situation at one situation at one moment in timemoment in time

e.g. Destination of e.g. Destination of full-time first full-time first degree graduatesdegree graduates

Time Series DataTime Series Data Gives values of Gives values of

same variable same variable (measured or (measured or counted) at counted) at different points in different points in timetime

e.g. Economic e.g. Economic activity and activity and inactivity of young inactivity of young peoplepeople

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-9

Levels of Measurement-Levels of Measurement-Numerical DataNumerical Data

A A ratio scale ratio scale is an ordered scale in is an ordered scale in which the difference between the which the difference between the measurements is a meaningful quantity measurements is a meaningful quantity and the measurements have a true and the measurements have a true zero point.zero point.

An An interval scaleinterval scale is an ordered scale is an ordered scale in which the difference between in which the difference between measurements is a meaningful quantity measurements is a meaningful quantity but the measurements do not have a but the measurements do not have a true zero point.true zero point.

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-10

Interval and Ratio ScalesInterval and Ratio Scales

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-11

Levels of Measurement-Levels of Measurement-Categorical DataCategorical Data

AA nominal scale nominal scale classifies data into classifies data into distinct categories in which no ranking is distinct categories in which no ranking is implied.implied.

Categorical Variables Categories

Personal Computer Ownership

Type of Stocks Owned

Internet Provider

Yes / No

Microsoft Network / AOL/ Other

Growth Value Other

Basic Business Statistics, 11e © 2009 Prentice-Hall, Inc.. Chap 1-12

Levels of Measurement-Levels of Measurement-Categorical DataCategorical Data

An An ordinal scale ordinal scale classifies data classifies data into distinct categories in which into distinct categories in which ranking is implied ranking is implied

Categorical Variable Ordered Categories

ServiceService Excellent, Good, Fair, PoorExcellent, Good, Fair, Poor

Product satisfactionProduct satisfaction Satisfied, Neutral, DissatisfiedSatisfied, Neutral, Dissatisfied

SizeSize Extra large, Large, Medium, Extra large, Large, Medium, SmallSmall

Standard & Poor’s bond ratingsStandard & Poor’s bond ratings AAA, AA, A, BBB, BB, B, CCC, AAA, AA, A, BBB, BB, B, CCC, CC, C, DDD, DD, DCC, C, DDD, DD, D

Student GradesStudent Grades A, B, C, D, FA, B, C, D, F