Fundamentals of Data Science - DS302 Lecture 2
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Questions and Answers

Detecting outliers is often the primary purpose of some data science applications like fraud detection.

True (A)

A dataset with fewer attributes is more prone to the curse of dimensionality.

False (B)

Sampling is a method used to select a subset of records to represent the original dataset.

True (A)

Including irrelevant attributes can improve the performance of a predictive model.

<p>False (B)</p> Signup and view all the answers

The error introduced by sampling is usually outweighed by the benefits of reducing the amount of data processed.

<p>True (A)</p> Signup and view all the answers

The data science process includes five phases: Understanding the problem, Preparing the data, Developing the model, Applying the model, and Deploying the models.

<p>True (A)</p> Signup and view all the answers

CRISP-DM is an acronym that stands for Cross Regional Innovation and Standard Process for Data Management.

<p>False (B)</p> Signup and view all the answers

Data mining is a relatively new concept and has no significant historical background.

<p>False (B)</p> Signup and view all the answers

The DMAIC framework is used for data science projects and stands for Define, Measure, Analyze, Improve, and Control.

<p>True (A)</p> Signup and view all the answers

The Knowledge Discovery in Databases process includes the phases: Selection, Preprocessing, Transformation, Data Mining, and Interpretation.

<p>True (A)</p> Signup and view all the answers

The Business Understanding phase of CRISP-DM only focuses on data collection without considering customer requirements.

<p>False (B)</p> Signup and view all the answers

The standard data science process framework consists of six phases.

<p>False (B)</p> Signup and view all the answers

SEMA stands for Sample, Explore, Modify, Model, and Assess, which is one of the frameworks used in data science.

<p>False (B)</p> Signup and view all the answers

Descriptive statistics help summarize the key characteristics of data distributions.

<p>True (A)</p> Signup and view all the answers

Outliers should be included in data analysis without any assessment.

<p>False (B)</p> Signup and view all the answers

Data exploration includes both computing descriptive statistics and visualizing data.

<p>True (A)</p> Signup and view all the answers

A credit score of 900 is an acceptable value for data accuracy.

<p>False (B)</p> Signup and view all the answers

The data science process relies solely on the quantity of data collected.

<p>False (B)</p> Signup and view all the answers

The interest rate typically decreases as the credit score increases.

<p>True (A)</p> Signup and view all the answers

A dataset is defined as a collection of data with a well-structured format.

<p>True (A)</p> Signup and view all the answers

Data cleansing practices do not include standardizing attribute values.

<p>False (B)</p> Signup and view all the answers

The label in a dataset refers to an input attribute that must be predicted.

<p>False (B)</p> Signup and view all the answers

Organizations benefit from maintaining data warehouses for higher data quality.

<p>True (A)</p> Signup and view all the answers

Preparing the dataset for data science tasks is usually the simplest part of the process.

<p>False (B)</p> Signup and view all the answers

Managing missing values first requires understanding the reasons behind their absence.

<p>True (A)</p> Signup and view all the answers

Identifiers are attributes used to provide context to individual records in a dataset.

<p>True (A)</p> Signup and view all the answers

In a data structure, each row represents a data point.

<p>True (A)</p> Signup and view all the answers

Data transformation is unnecessary if the data is originally in a tabular format.

<p>True (A)</p> Signup and view all the answers

Quality of data is less important than availability when answering business questions.

<p>False (B)</p> Signup and view all the answers

The fundamental objective of any data science process is to address the analysis question.

<p>True (A)</p> Signup and view all the answers

Prior knowledge refers to data that is yet to be discovered about a subject.

<p>False (B)</p> Signup and view all the answers

A well-defined statement of the problem is crucial for selecting the right dataset in the data science process.

<p>True (A)</p> Signup and view all the answers

Data science can use any kind of algorithm without concern for the business question being addressed.

<p>False (B)</p> Signup and view all the answers

It is possible to ignore the subject matter expertise in the data science process.

<p>False (B)</p> Signup and view all the answers

Spurious signals in data science refer to genuine patterns that are highly relevant to the analysis.

<p>False (B)</p> Signup and view all the answers

The data science process is a linear series of steps that must be followed exactly.

<p>False (B)</p> Signup and view all the answers

Custom coding is one of the software tools that can be used to implement data science algorithms.

<p>True (A)</p> Signup and view all the answers

Missing credit score values can only be replaced with the mean value of the dataset.

<p>False (B)</p> Signup and view all the answers

Data records with missing values can be ignored to build a representative model.

<p>True (A)</p> Signup and view all the answers

In linear regression models, input attributes can be categorical.

<p>False (B)</p> Signup and view all the answers

Binning is a technique used to convert categorical data into numeric values.

<p>False (B)</p> Signup and view all the answers

Normalization helps prevent one attribute from dominating distance calculations in algorithms like k-NN.

<p>True (A)</p> Signup and view all the answers

Outliers are considered normal variations in a dataset.

<p>False (B)</p> Signup and view all the answers

Income and credit score must be on the same scale for distance calculations in clustering algorithms.

<p>True (A)</p> Signup and view all the answers

The presence of outliers in a dataset is inconsequential and does not require any action.

<p>False (B)</p> Signup and view all the answers

Flashcards

Data Science Process

A set of iterative activities for discovering useful patterns and relationships in data.

Data Science Process Steps

Understanding the problem, preparing data, developing a model, applying it, deploying, and maintaining the model.

CRISP-DM

Cross Industry Standard Process for Data Mining, a widely used framework for data science projects.

Why Data Science is Important

Huge amounts of data and the pressing need to extract useful information and knowledge from that data.

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Data Science Process Frameworks

Methods like CRISP-DM, SEMMA, DMAIC, that structure data science methodologies.

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Business Understanding

The crucial phase to understand the project's goals and customer needs in data science projects.

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Data Science Process

A general set of steps for data analysis, independent of the specific problem, algorithm, or tool.

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Data Understanding

The step of identifying, collecting, and analyzing a dataset in the data science process.

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Prior Knowledge

Existing information about the subject of the analysis, including the problem's objective, subject area, and data.

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Objective of the problem

The specific analytical goal or business objective driving the data science process.

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Subject area of the problem

The context and business process that generated the data, crucial for interpreting patterns.

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Analysis Question

The question or objective that the data science process aims to answer.

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Data

The information collected to answer the question.

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Business Question

The problem the data science steps are designed to solve from a business perspective.

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Prior Knowledge (Data)

Gathering information about how data is collected, stored, transformed, reported, and used to answer a business question.

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Data Quality

Assessing the accuracy, completeness, and consistency of data.

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Data Quantity

Evaluating the amount of available data.

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Data Availability

Checking the accessibility of the data.

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Data Gaps

Identifying missing or incomplete data.

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Dataset

Structured collection of data with rows (records) and columns (attributes).

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Data Point

A single instance of data within a dataset, represented by a row in a table.

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Label (Data)

The attribute in a dataset to be predicted or classified – the target variable.

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Identifier (Data)

Special attribute used to identify or locate individual records (e.g., account numbers).

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Data Preparation

Transforming data into a suitable format for data science algorithms.

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Data Exploration

Initial investigation of data to understand its characteristics and patterns.

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Data Transformation

Changing the format of the data.

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Missing Values

Records with absent attribute values in a dataset.

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Data Quality Issues

Errors or inconsistencies in data that might affect the model's accuracy.

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Data Exploration

Analyzing data to understand its structure, distribution, and relationships.

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Descriptive Statistics

Summary measures like mean, median, mode, standard deviation, and range for data distribution.

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Data Cleansing

Techniques to improve data quality, such as removing duplicates, outliers, and standardizing values.

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Data Warehouse

Centralized repository for company data, often with a high level of data quality and accuracy.

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Outliers

Data points that significantly deviate from the rest of the data.

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Feature Selection

Choosing the most relevant features (attributes) from a dataset for analysis or modeling.

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Sampling

Selecting a subset of data for analysis when working with large datasets.

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Missing Credit Scores

Missing credit score values can be replaced with a credit score derived from the dataset (mean, minimum, or maximum value).

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Rare Missing Values

Useful when missing values occur randomly and infrequently in a dataset.

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Ignoring Poor Data

Remove records with missing values or poor data quality to simplify model building and reduce dataset size.

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Data Type Conversion

Convert data attributes from different types (categorical, numeric) into the same format, often numeric.

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Categorical to Numeric

Transform categorical attributes into numerical representations.

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Numeric to Categorical

Convert numeric attributes into categorical data.

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Normalization

Rescale numeric attributes to a specific range (e.g., 0 to 1) to avoid attribute dominance in distance calculation methods.

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Outliers

Anomalies in a dataset that represent unusual values.

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Outlier Detection

Identifying unusual data points in a dataset, which may be important for fraud or intrusion detection.

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Feature Selection

Choosing the most important attributes from a dataset to improve model performance and reduce complexity.

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Curse of Dimensionality

The increased complexity of a model with a large number of attributes (features).

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Sampling

Selecting a smaller representative subset of data for analysis or modelling to speed up the process.

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Dataset Attributes

The measurable characteristics of the data.

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Dataset Label

The characteristic of the dataset that you are predicting.

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Study Notes

Fundamentals of Data Science - DS302

  • Course taught by Dr. Nermeen Ghazy
  • Reference books include:
    • Data Science: Concepts and Practice, Vijay Kotu and Bala Deshpande, 2019
    • DATA SCIENCE: FOUNDATION & FUNDAMENTALS, B. S. V. Vatika, L. C. Dabra, Gwalior, 2023

Lecture 2 - Data Science Process

  • Data science is a process of discovering relationships and patterns in data
  • It involves iterative activities
  • The standard data science process includes:
    • Understanding the problem
    • Preparing data samples
    • Developing a model
    • Applying the model to a dataset
    • Deploying and maintaining models

Key Steps in Data Science

  • Prior Knowledge: This involves understanding the problem's objective, the subject area, and the data itself.
  • Preparation: This involves exploring, defining issues of data quality, handling missing values, converting data types, transforming data, removing outliers, and then sampling.
  • Modeling: This involves building and applying models.
  • Application: This involves using the model on data.
  • Knowledge: This involves gaining knowledge based on the findings.

Data Science Process - CRISP-DM

  • CRISP-DM is a six-phased process model
  • It naturally describes the data science life cycle, analogous to a set of roadmaps

Why Data Science is Important

  • Huge amount of available data
  • Need to transform data into valuable insights and knowledge
  • Natural evolution of information technology

Data Science Process Framework

  • Common data science frameworks include:
    • CRISP-DM (Cross Industry Standard Process for Data Mining)
    • SEMMA (Sample, Explore, Modify, Model, and Assess)
    • DMAIC (Define, Measure, Analyze, Improve, and Control), used in Six Sigma practice.

CRISP-DM Process Steps

  • Business Understanding: Understand project objectives and customer needs
  • Data Understanding: Identify, collect, analyze data sets
  • Data Preparation: Focus on preprocessing, transformation, and modification of data. Explore various methods for handling missing data: mean, minimum, maximum, etc. Note that converting data to be used within a linear regression model requires numerical values. Different methods such as binning can be used to convert continuous data to categorical data. Focus on data structures (e.g. data frame).
  • Modeling: Build and apply models
  • Evaluation: Model evaluation and improvement.
  • Deployment: Deployment and maintenance of models

Prior Knowledge

  • Refers to existing information about a subject
  • Guides problem definition, context, and required data
  • Key components include:
    • Problem objective
    • Subject area
    • Data

Data

  • Factors to consider include quality, quantity, availability, gaps, etc
  • Understanding the data collection and reporting is essential in data science
  • Dataset: Collection of data with defined structure
  • Data point: Single instance in the dataset. Also known as record, object, or example.

Data Preparation

  • This is often the most time-consuming part of the process.
  • Datasets are rarely in the required form for algorithms.
  • Tabular format (records in rows, attributes in columns) is usually required.

Data Preparation Steps

  • Data exploration
  • Data quality
  • Handling missing values
  • Data type conversion
  • Transformation
  • Feature selection
  • Sampling

Data Exploration

  • Aims to understand characteristics of a dataset
  • Includes descriptive statistics and visualizations
  • Shows dataset structure, value distributions, extreme values, and inter-relationship of attributes

Data Quality

  • A critical aspect of data science
  • Deals with accuracy, completeness, consistency, and timeliness of data.

Handling Missing Values

  • One of the common data quality issues
  • Various methods exist to deal with missing values

Data Type Conversion

  • Converting data to the suitable data type for a specific model.
  • Continuous or numeric attributes may need to become continuous or categorical.

Transformation

  • Normalization plays an important role, preventing any one attribute from dominating results due to large attribute values. Useful in algorithms such as k-nearest neighbor where comparisons of one dataset to another are made. Normalization usually converts a dataset into a more uniform scale between 0 and 1.

Outliers

  • Abnormal values in a dataset
  • May have to be identified and managed based on their origin
  • These values need special consideration

Feature Selection

  • Identifying relevant attributes needed to train a model
  • Helps in mitigating issues with dimensionality

Sampling

  • Selecting a subset of data to represent the original dataset
  • Reduces processing time

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This quiz covers the key steps involved in the data science process as outlined in DS302. Participants will explore essential activities such as problem understanding, data preparation, model development, and deployment. Test your knowledge of the iterative nature and methodologies in data science.

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