Podcast
Questions and Answers
Which attribute type includes values with a meaningful order but unknown magnitude between successive values?
Which attribute type includes values with a meaningful order but unknown magnitude between successive values?
- Discrete
- Ordinal (correct)
- Nominal
- Binary
Which of the following is an example of a ratio-scaled attribute?
Which of the following is an example of a ratio-scaled attribute?
- Temperature in Celsius
- Weight in kilograms (correct)
- Hair color
- Army rankings
What best describes a binary attribute?
What best describes a binary attribute?
- A nominal attribute with only two states. (correct)
- An attribute with three or more possible values.
- An attribute that can take on any numeric value.
- An attribute that is always measurable on an ordered scale.
In which of the following scenarios would you use an interval-scaled attribute?
In which of the following scenarios would you use an interval-scaled attribute?
Which of the following is NOT a characteristic of nominal attributes?
Which of the following is NOT a characteristic of nominal attributes?
What is a common issue with manually filling in missing values?
What is a common issue with manually filling in missing values?
Which of the following methods is considered smarter for filling in missing values?
Which of the following methods is considered smarter for filling in missing values?
What causes noise in data?
What causes noise in data?
Which of the following is NOT listed as a problem associated with data?
Which of the following is NOT listed as a problem associated with data?
What is the purpose of binning in handling noisy data?
What is the purpose of binning in handling noisy data?
What does the cosine similarity formula calculate?
What does the cosine similarity formula calculate?
What is a common issue encountered when integrating multiple databases?
What is a common issue encountered when integrating multiple databases?
Which operation is used to calculate the dot product of two vectors?
Which operation is used to calculate the dot product of two vectors?
Which of the following is NOT a method of data transformation?
Which of the following is NOT a method of data transformation?
What is the significance of calculating the lengths of vectors in cosine similarity?
What is the significance of calculating the lengths of vectors in cosine similarity?
What issue do traditional similarity measures face?
What issue do traditional similarity measures face?
What does the min-max normalization formula achieve?
What does the min-max normalization formula achieve?
Which of the following is an attribute that may vary across different databases?
Which of the following is an attribute that may vary across different databases?
How is the cosine similarity value represented mathematically?
How is the cosine similarity value represented mathematically?
What method can be used to detect redundant attributes within datasets?
What method can be used to detect redundant attributes within datasets?
Which example illustrates the limitation of vector space models?
Which example illustrates the limitation of vector space models?
Which of the following describes 'smoothing' in data transformation?
Which of the following describes 'smoothing' in data transformation?
What new methods are suggested for handling complex semantics?
What new methods are suggested for handling complex semantics?
What is the primary purpose of discretization in data transformation?
What is the primary purpose of discretization in data transformation?
What fundamental aspect do data quality and data cleaning focus on?
What fundamental aspect do data quality and data cleaning focus on?
What does attribute construction involve in data transformation?
What does attribute construction involve in data transformation?
What does a boxplot represent regarding a dataset?
What does a boxplot represent regarding a dataset?
What is the inter-quartile range (IQR)?
What is the inter-quartile range (IQR)?
What does a quantile-quantile (q-q) plot compare?
What does a quantile-quantile (q-q) plot compare?
Which statement about positively and negatively correlated data is true?
Which statement about positively and negatively correlated data is true?
Which of the following describes an ordinal variable?
Which of the following describes an ordinal variable?
What is the correct threshold for identifying potential outliers in a dataset using IQR?
What is the correct threshold for identifying potential outliers in a dataset using IQR?
In a scatter plot, what does each point represent?
In a scatter plot, what does each point represent?
What can cosine similarity be used to measure?
What can cosine similarity be used to measure?
Which of the following is NOT part of the five-number summary?
Which of the following is NOT part of the five-number summary?
How is the distance between ordinal values calculated?
How is the distance between ordinal values calculated?
What is a key limitation when using equal-frequency partitioning for data presentation?
What is a key limitation when using equal-frequency partitioning for data presentation?
Which method is employed in smoothing data using the binning approach?
Which method is employed in smoothing data using the binning approach?
What is a common challenge when managing categorical attributes in data processing?
What is a common challenge when managing categorical attributes in data processing?
What characterizes lossless compression in data handling?
What characterizes lossless compression in data handling?
Which of the following is true regarding audio/video compression?
Which of the following is true regarding audio/video compression?
What does the term 'bin boundaries' refer to in the context of data smoothing?
What does the term 'bin boundaries' refer to in the context of data smoothing?
What happens to outliers when using straightforward data representation methods?
What happens to outliers when using straightforward data representation methods?
What is the result of using equal-depth partitioning?
What is the result of using equal-depth partitioning?
Flashcards
Nominal Attribute
Nominal Attribute
Categorical data where values represent distinct groups or states with no inherent order. Examples include hair color, marital status, and zip codes.
Binary Attribute
Binary Attribute
A nominal attribute with only two possible states, typically represented by 0 and 1. Examples include gender or a medical test result (positive/negative).
Ordinal Attribute
Ordinal Attribute
A type of attribute where the order of values matters, but the difference between them is not defined. Examples include grades (A, B, C), army rankings, or size categories (small, medium, large).
Interval Attribute
Interval Attribute
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Ratio Attribute
Ratio Attribute
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Noise
Noise
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Causes of Noisy Data
Causes of Noisy Data
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Global Constant for Missing Values
Global Constant for Missing Values
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Binning
Binning
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Smoothing Data using Binning
Smoothing Data using Binning
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Cosine similarity
Cosine similarity
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Data Preprocessing
Data Preprocessing
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Data Cleaning
Data Cleaning
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Data Integration
Data Integration
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Vector Space Model
Vector Space Model
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Hidden Semantics
Hidden Semantics
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Distributive Representation
Distributive Representation
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Representational Learning
Representational Learning
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Object Identification
Object Identification
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Derivable Data
Derivable Data
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Redundancy in Data Integration
Redundancy in Data Integration
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Normalization
Normalization
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Discretization
Discretization
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Data Compression
Data Compression
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Sampling
Sampling
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Data Transformation
Data Transformation
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Scatter Plot
Scatter Plot
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Quantile-Quantile Plot (Q-Q Plot)
Quantile-Quantile Plot (Q-Q Plot)
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Boxplot
Boxplot
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Inter-Quartile Range (IQR)
Inter-Quartile Range (IQR)
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Five Number Summary
Five Number Summary
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Outliers (in Box Plot)
Outliers (in Box Plot)
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Ordinal Variable
Ordinal Variable
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Bag of Terms Representation
Bag of Terms Representation
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Positively Correlated Data
Positively Correlated Data
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Equal-depth Partititoning
Equal-depth Partititoning
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Smoothing by Bin Means
Smoothing by Bin Means
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Smoothing by Bin Boundaries
Smoothing by Bin Boundaries
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Lossless String Compression
Lossless String Compression
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Lossy Audio/Video Compression
Lossy Audio/Video Compression
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Progressive Refinement
Progressive Refinement
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Fragment Reconstruction
Fragment Reconstruction
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Study Notes
Data, Measurements, and Data Preprocessing
- This chapter covers various types of data sets and methods for preprocessing data.
- Data types include relational records, data matrices (e.g., numerical matrices, crosstabs), transaction data, and document data (represented as term-frequency vectors).
- Graphs and networks are also mentioned, including transportation networks, World Wide Web, molecular structures, and social/information networks.
- Ordered data is presented, including video data (sequences of images), temporal data (time series), sequential data (transaction sequences), and genetic sequence data.
Types of Data Sets
- (1) Record Data: Relational records—highly structured relational tables, data matrices, crosstabs are included
- Various examples of data, like records for persons and cars in a data set are shown, including a data matrix example.
- (2) Graphs and Networks: Transportation network, World Wide Web, molecular structures, and social/information networks are discussed.
- (3) Ordered Data: Video data, temporal data (time-series), sequential data (transaction sequences). Genetic sequence data are examples.
- (4) Spatial, Image, and Multimedia Data: Spatial data (maps, vector and raster representations) and image and video data are included.
Data Objects
- Data sets consist of data objects.
- Each data object represents an entity.
- Examples given are sales databases (customers, items, sales), medical databases (patients, treatments) and university databases (students, professors, courses)
- Data objects are characterized by attributes.
- Database rows represent data objects, while columns represent attributes.
Attributes
- Attributes are characteristics or features/variables of a data object.
- Examples are customer ID, name, and address.
- Attribute types include nominal (e.g., red, blue), binary (e.g., true, false), ordinal (e.g., freshman, sophomore), numeric (quantitative), interval-scaled, and ratio-scaled.
- Discrete attributes have finite or countably infinite values; continuous attributes have real-valued attribute values.
Attribute Types
- Nominal: Categorical values (e.g., hair color, marital status)
- Binary: Two states (0/1 or true/false) - symmetric (equal importance) or asymmetric (unequal importance).
- Ordinal: Values with a meaningful order (e.g., grades, rankings).
- Numeric: Quantitative values; further categorized as:
- Interval-scaled: Differences between values are meaningful (e.g., Celsius temperature, calendar dates)
- Ratio-scaled: Values have a true zero point (e.g., Kelvin temperature, length, counts)
Statistics of Data
- Measures of central tendency (mean, median, mode) and dispersion are important for understanding the data distribution
- Covariance and correlation analysis reveal the relationship between numerical variables.
- Graphs display basic statistical descriptions like boxplots, histograms, quantile plots, scatter plots.
Measuring the Central Tendency
- Mean: The average value (algebraic measure, sample vs. population)
- Weighted arithmetic mean: Multiplies each value by its corresponding weight.
- Trimmed mean: Removes extreme values.
- Median: The middle value. Estimable by interpolation on grouped data.
- Mode: The most frequent value.
Measuring the Dispersion of Data
- Quartiles: Q₁ (25th percentile), Q₃ (75th percentile), and the Interquartile Range (IQR).
- Five-number summary: Min, Q₁, median, Q₃, and Max.
- Boxplots: Graphical representation of the five-number summary.
- Outliers are discussed.
Measuring Data Distribution
- Variance: A measure of the spread of data points around the mean.
- Standard deviation: The square root of variance.
- Formulas for sample and population variances/standard deviations are included.
Correlation
- Correlation measures the linear relationship between two numerical variables.
- It's computed as the normalized covariance between the variables.
- Correlation values range from -1 to 1; values near 1 indicate positive correlation; near -1 indicates negative correlation; values near 0 indicate no correlation.
Visualizing Changes of Correlation Coefficients
- Scatter plots can visualize correlation coefficients varying between -1 and 1.
Graphic Displays of Basic Statistical Descriptions
-
Boxplots: Graphically show the five-number summary (minimum, Q1, median, Q3, maximum).
-
Histograms: Display data frequencies by creating bins of values along the X-axis.
-
Quantile plots: Pairs a value with its rank to show data distribution.
-
Scatter plots: Plot pairs of values of two attributes.
Data Quality Issues
- The discussed measures of data quality include accuracy, completeness, consistency and believability, and interpretability
Data Cleaning
- Incomplete data: Missing attribute values
- Noisy data: Errors or variations
- Inconsistency data: Different representations or values for the same entity
- Methods for handling missing and noisy data include binning, smoothing, clustering, and detecting outliers
- Handling: Ignore, imputation (fill in missing values; various techniques like mean, most frequent, global constant, etc.).
Data Integration
- Combining data from multiple sources (databases, data cubes, files).
- Goals include reducing noise, obtaining a more complete data view, and improving the speed and quality of data mining.
- Methods include schema integration (e.g., merging metadata from different sources), entity identification (identifying real-world entities in different data sources having different names), and handling data value conflicts (e.g., conflicting values of the same attribute in different files for the same real-world object)
Data Transformation
- Normalization: Scaling data to fall in a specified range (e.g., min-max, z-score, normalization by decimal scaling)
- Discretization: Converting continuous data into categorical data (e.g., equal-width, equal-frequency)
- Data compression : Reduce data size.
- Sampling: Reducing data set size by selecting a representative subset.
Automatic Concept Hierarchy Generation
- Methods to automatically create a hierarchical structure from attributes,
- Examples (weekday, month, quarter, year, country, province/state, city, street) are included.
Sampling
- Methods for selecting a representative subset from a large data set.
- Sampling methods include simple random sampling, stratified sampling.
Cosine Similarity
- Cosine similarity is a measure of the similarity between two vectors (e.g., term-frequency vectors, gene feature vectors).
- It's used to determine the degree of similarity between two documents (or other objects) based on the angle between their vectors in a vector space.
- The formula for cosine similarity is given.
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Description
Test your knowledge on data attributes including nominal, ordinal, interval, and ratio scales. Learn about handling missing values, data noise, and the purpose of binning in data processing. This quiz covers key concepts important for data handling and analysis.