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27 jan 2021 · What is Data? Collection of data objects and their attributes An attribute is a property or characteristic of an object

Decision Trees Data Mining Lecture 2 3 What is Data? • Collection of data objects and their attributes • An attribute is a property or characteristic of an object –

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27 jan 2021 · What is Data? Collection of data objects and their attributes An attribute is a property or characteristic of an object

[PDF] Data Mining: Data

Collection of data objects and their attributes • An attribute is a property or characteristic of an object – Examples: eye color of a person, temperature, etc

1 Introduction 2 Attributes, Data Sets, and Data Storage

For instance, some preprocessing and data mining methods are only applicable to data described by discrete features In those cases a process called

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What's in an attribute? Nominal, ordinal, interval, ratio Preparing the input ARFF, attributes, missing values, getting

Data Mining: Practical Machine Learning Tools and Techniques (Chapter 7) Engineering the input and output ○ Attribute selection ♢ Schemeindependent

[PDF] A Comparison of Several Approaches to Missing Attribute - NJIT

Missing Attribute Values in Data Mining Jerzy W Grzymala-Busse1 and Ming Hu2 1 Department of Electrical Engineering and Computer Science University of

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– Often represented as integer variables – Note: binary attributes are a special case of discrete attributes ○ Continuous Attribute –

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il y a 4 jours · Attributes: measuring aspects of an instance ○ We will focus on nominal and numeric attributes Most common form in practical data mining

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01/27/20211Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Data Mining: Data

Lecture Notes for Chapter 2

Introduction to Data Mining , 2

Edition

Tan, Steinbach, Kumar

01/27/20212Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Outline

Attributes and Objects

Types of Data

Data Quality

Similarity and Distance

Data Preprocessing

1 2

What is Data?

Collection of data objects

and their attributes

An attributeis a property

or characteristic of an object -Examples: eye color of a person, temperature, etc. -Attribute is also known as variable, field, characteristic, dimension, or feature

A collection of attributes

describe an object -Object is also known as record, point, case, sample, entity, or instance

Tid Refund Marital

Status

Taxable

Income

Cheat

1 Yes Single 125K No

2 No Married 100K No

3 No Single 70K No

4 Yes Married 120K No

5 No Divorced 95K Yes

6 No Married 60K No

7 Yes Divorced 220K No

8 No Single 85K Yes

9 No Married 75K No

10 No Single 90K Yes

Attributes

Objects

01/27/20214Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Attribute Values

Attribute valuesare numbers or symbols

assigned to an attribute for a particular object Distinction between attributes and attribute values -Same attribute can be mapped to different attribute values

Example: height can be measured in feet or meters

-Different attributes can be mapped to the same set of values Example: Attribute values for ID and age are integers -But properties of attribute can be different than the properties of the values used to represent the attribute 3 4

Measurement of Length

The way you measure an attribute may not match the attributes properties. 1 2 3 55
7 8 15 10 4A B C D E

This scale

preserves the ordering and additvity properties of length.This scale preserves only the ordering property of length.

01/27/20216Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Types of Attributes

There are different types of attributes

-Nominal

Examples: ID numbers, eye color, zip codes

-Ordinal Examples: rankings (e.g., taste of potato chips on a scale from 1-10), grades, height {tall, medium, short} -Interval Examples: calendar dates, temperatures in Celsius or

Fahrenheit.

-Ratio

Examples: temperature in Kelvin, length, counts,

elapsed time (e.g., time to run a race) 5 6

01/27/20217Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Properties of Attribute Values

The type of an attribute depends on which of the following properties/operations it possesses: -Distinctness: = -Order: < > -Differences are+ - meaningful : -Ratios are meaningful -Nominal attribute: distinctness -Ordinal attribute: distinctness & order -Interval attribute: distinctness, order & meaningful differences -Ratio attribute: all 4 properties/operations

01/27/20218Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Difference Between Ratio and Interval

Is it physically meaningful to say that a

temperature of 10 °is twice that of 5°on -the Celsius scale? -the Fahrenheit scale? -the Kelvin scale?

Consider measuring the height above average

-If Bill's height is three inches above average and Bob's height is six inches above average, then would we say that Bob is twice as tall as Bill? -Is this situation analogous to that of temperature? 7 8

Attribute

Type

Description

Examples

Operations

Nominal

Nominal attribute

values only distinguish. (=, ) zip codes, employee

ID numbers, eye

color, sex: {male, female} mode, entropy, contingency correlation, 2 test

Categorical

Qualitative

Ordinal Ordinal attribute

values also order objects. (<, >) hardness of minerals, {good, better, best}, grades, street numbers median, percentiles, rank correlation, run tests, sign tests

Interval For interval

attributes, differences between values are meaningful. (+, - ) calendar dates, temperature in

[PDF] [PDF] Data Mining - Computer Science & Engineering User Home Pages

01/27/20211Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Data Mining: Data

Lecture Notes for Chapter 2

Introduction to Data Mining , 2

Edition

Tan, Steinbach, Kumar

01/27/20212Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Outline

Attributes and Objects

Types of Data

Data Quality

Similarity and Distance

Data Preprocessing

What is Data?

Collection of data objects

An attributeis a property

A collection of attributes

Tid Refund Marital

Status

Taxable

Income

1 Yes Single 125K No

2 No Married 100K No

3 No Single 70K No

4 Yes Married 120K No

5 No Divorced 95K Yes

6 No Married 60K No

7 Yes Divorced 220K No

8 No Single 85K Yes

9 No Married 75K No

10 No Single 90K Yes

Attributes

Objects

01/27/20214Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Attribute Values

Attribute valuesare numbers or symbols

Example: height can be measured in feet or meters

Measurement of Length

This scale

01/27/20216Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Types of Attributes

There are different types of attributes

Examples: ID numbers, eye color, zip codes

Fahrenheit.

Examples: temperature in Kelvin, length, counts,

01/27/20217Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Properties of Attribute Values

01/27/20218Introduction to Data Mining, 2nd Edition

Tan, Steinbach, Karpatne, Kumar

Difference Between Ratio and Interval

Is it physically meaningful to say that a

Consider measuring the height above average

Attribute

Description

Examples

Operations

Nominal

Nominal attribute

ID numbers, eye

Categorical

Qualitative

Ordinal Ordinal attribute

Interval For interval

Celsius or Fahrenheit mean, standard

Pearson's

F tests

Numeric

Quantitative

Ratio For ratio variables,