Data Validation and Standardization Quiz

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Questions and Answers

What is a method for correcting address data using geographic names?

  • Employing social security numbers
  • Verifying phone numbers
  • Using online search engines
  • Using dictionaries on geographic names and zip codes (correct)

What constitutes an age validation error based on the specified rules?

  • An age of 25
  • An age of 30
  • An age of 50
  • An age of 70 (correct)

In a validation rule that requires certain categorical values, which of the following would be detected as an error?

  • Category W (correct)
  • Category B
  • Category C
  • Category A

Which of the following can lead to ambiguous values in data entry?

<p>Employing the same category value for different meanings (C)</p> Signup and view all the answers

Why is standardizing data values necessary?

<p>To ensure values are consistent and have a uniform format (A)</p> Signup and view all the answers

Which of the following date representations demonstrates a lack of standardization?

<p>October 19, 2009 (D)</p> Signup and view all the answers

What is one example of standardizing string data?

<p>Converting names to upper or lower case (D)</p> Signup and view all the answers

What is a correct procedure for resolving abbreviations in data?

<p>Applying predefined conversion rules (C)</p> Signup and view all the answers

What is the first step in managing missing values in a dataset?

<p>Understand the reason behind why the values are missing (D)</p> Signup and view all the answers

Which method is most appropriate for handling missing values that occur randomly and infrequently?

<p>Replacing missing values with the mean or median value (B)</p> Signup and view all the answers

What must be done to categorical data before using linear regression models?

<p>It must be converted to continuous numeric attributes. (C)</p> Signup and view all the answers

What is the purpose of normalization in algorithms like k-nearest neighbor (k-NN)?

<p>To eliminate the influence of minor attribute variations (B)</p> Signup and view all the answers

How can numeric values be transformed into categorical data?

<p>By using the binning technique (A)</p> Signup and view all the answers

What is a consequence of ignoring records with missing or poor data quality?

<p>It may lead to biased results due to selective data removal. (B)</p> Signup and view all the answers

Which attribute type is typically used for interest rates in a dataset?

<p>Continuous numeric (D)</p> Signup and view all the answers

In data transformation, what scale can attributes be normalized to?

<p>0 to 1 (A)</p> Signup and view all the answers

What are outliers in a dataset?

<p>Anomalies that can occur due to accurate or erroneous data capture (C)</p> Signup and view all the answers

Why does a large number of attributes in a dataset create challenges?

<p>It may lead to the curse of dimensionality, complicating models (D)</p> Signup and view all the answers

What is the main purpose of sampling in data analysis?

<p>To reduce processing time with a representative subset (C)</p> Signup and view all the answers

Which of the following best describes a model in the context of data science?

<p>An abstract representation of data and relationships (C)</p> Signup and view all the answers

What is true about association analysis and clustering techniques?

<p>They do not involve prediction and lack a test dataset (B)</p> Signup and view all the answers

What is the purpose of identifying outliers in a data set?

<p>To ensure they are not caused by data entry errors. (C)</p> Signup and view all the answers

What is a significant risk of using sampling in data science?

<p>Errors introduced that may affect the model's relevancy (C)</p> Signup and view all the answers

Which statement about feature selection is correct?

<p>Feature selection helps identify useful attributes for predictions (B)</p> Signup and view all the answers

Which quartile divides the data set into two equal halves?

<p>Q2 (B)</p> Signup and view all the answers

How is the first quartile (Q1) calculated?

<p>It is the median of the lower half of the data. (D)</p> Signup and view all the answers

What can outliers indicate in a dataset?

<p>They can indicate unique or rare occurrences within data (C)</p> Signup and view all the answers

In the example data set 6, 47, 49, 15, 42, 41, 7, 39, 43, 40, 36, what is the value of Q3?

<p>43 (C)</p> Signup and view all the answers

When computing quartiles, what should be done if the median is also one of the data items?

<p>Exclude it from any further computations. (C)</p> Signup and view all the answers

What is the first step to compute Q1, Q2, and Q3?

<p>Order the given data set in ascending order. (B)</p> Signup and view all the answers

For the data set 39, 36, 7, 40, 41, 17, what is the value of Q2?

<p>37.5 (B)</p> Signup and view all the answers

What percentage of data items does Q1 cut off from the lowest end?

<p>25% (A)</p> Signup and view all the answers

What is a primary objective of data exploration?

<p>To identify and analyze anomalies in datasets. (D)</p> Signup and view all the answers

Which type of data exploration focuses on a single attribute at a time?

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

Which of the following is NOT an attribute of the Iris dataset?

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

Scatterplots in data exploration are primarily used for which purpose?

<p>To identify clusters in low-dimensional data. (A)</p> Signup and view all the answers

Which of the following correctly describes descriptive statistics?

<p>It summarizes aggregate quantities of a dataset. (A)</p> Signup and view all the answers

What is one benefit of using histograms in data exploration?

<p>They visualize data distribution and error rate estimation. (D)</p> Signup and view all the answers

The Iris dataset consists of how many observations for each species?

<p>50 (A)</p> Signup and view all the answers

Which type of exploration considers multiple attributes simultaneously?

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

What does the symbol r represent in statistics?

<p>Sample correlation coefficient (D)</p> Signup and view all the answers

What is the range of values for the correlation coefficient r?

<p>-1 to 1 (B)</p> Signup and view all the answers

If two variables have a correlation coefficient r close to -1, what does this indicate?

<p>A strong negative linear correlation (B)</p> Signup and view all the answers

Which of the following is NOT a motivation for using data visualization?

<p>Elimination of numerical data (B)</p> Signup and view all the answers

What type of visualization focuses on the relationship between one attribute and another?

<p>Multivariate visualization (C)</p> Signup and view all the answers

Which method is NOT a common approach for visualizing data relationships?

<p>Using numerical data only (D)</p> Signup and view all the answers

What is the main benefit of visualizing data in a scatter plot?

<p>To easily see patterns or correlations between two variables (A)</p> Signup and view all the answers

How does univariate visualization assist in data exploration?

<p>By investigating the distribution of a single attribute (B)</p> Signup and view all the answers

Flashcards

Outliers

Values in a data set that are significantly different from the other values. They may indicate errors or unusual circumstances.

Interquartile Range (IQR) Method

A method for identifying and handling outliers by calculating the interquartile range (IQR) and identifying values that fall outside of a specific range.

Interquartile Range (IQR)

The difference between the third quartile (Q3) and the first quartile (Q1) of a data set. It represents the range of the middle 50% of the data.

Quartiles

The values that divide a sorted data set into four equal parts.

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First Quartile (Q1)

The first quartile (Q1) cuts off the lowest 25% of the data in a sorted data set.

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Second Quartile (Q2)

The second quartile (Q2) is the median of the data set, dividing it in half.

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Third Quartile (Q3)

The third quartile (Q3) cuts off the highest 25% of the data or, equivalently, the lowest 75% of the data.

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Ascending Order

The process of arranging a data set in ascending order.

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Data Validation

This involves identifying and correcting errors in data that do not conform to expected patterns or rules.

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Validation Rules

Ensuring that data values follow predefined rules, such as age limits or allowable categories.

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Ambiguous Values

This involves identifying and correcting cases where a single value has multiple interpretations.

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Data Standardization

A process of making data consistent by applying specific formats or rules for dates, times, names, and abbreviations.

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Standardizing Dates

Converting data to a pre-defined format, like “10/19/2009” instead of “Oct. 19, 2009” to ensure consistency.

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Standardizing Names

Converting names to a uniform format, like either all uppercase or lowercase, for consistent representation.

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Standardizing Titles

Removing prefixes and suffixes from names, for streamlined data representation.

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Standardizing Abbreviations

Resolving abbreviations and encoding schemes by using dictionaries or predefined rules.

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Handling Missing Values

When some values are missing in a dataset, it can cause trouble. It's like having a recipe with missing ingredients! We need to figure out why the data is missing, and then use techniques to fill in the gaps.

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Ignoring Records

One way to deal with missing values is to pretend they're not there. We can simply remove the entire row (record) with the missing value. It's like crossing out the whole recipe if one ingredient is missing.

This is a simple approach, but it can reduce the amount of data we have.

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Replacing Missing Values

We can fill in the missing value with the average or most common value from the rest of the data. Imagine replacing a missing ingredient with the most common ingredient used in other recipes like it.

It's a quick fix, but it might not be the most accurate.

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Data Type Conversion

Data can exist in different forms like numbers (like a score) and categories (like good, bad, excellent). Just like a recipe can use ingredients in different forms (like whole grains and chopped veggies). This step involves making sure the data is in the right form for our analysis.

For example, linear regression models can only work with numbers, so we can convert the categories to numbers. It's like using measurements instead of words in a recipe.

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Binning

This is like grouping similar ingredients together in a recipe. For example, we might group a range of credit scores into categories like 'low', 'medium', and 'high'.

It simplifies our analysis, but it's important to choose the right groups!

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Data Transformations

Sometimes, we need to scale our data to make it comparable. Imagine a recipe that uses measurements in cups for some ingredients and grams for others. This step is like converting all measurements to grams for consistency. This helps us compare different elements of the data fairly.

It's like making sure all the ingredients are measured using the same unit!

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Normalization

Think of it like trying to compare different ingredients by their size. This technique scales the data to a range from 0 to 1. It helps ensure that one ingredient doesn't overshadow others due to a larger scale.

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Data Preparation

This process ensures that all the ingredients are ready for the cooking process. It's important to be mindful of different data cleaning steps to ensure the quality of your data. This makes sure we can analyze our data accurately

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Data Exploration

Data exploration is the process of examining raw data to identify patterns, trends, and anomalies before applying any statistical methods.

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Missing Values

Missing values are gaps in a dataset where data is not available. They can be caused by errors in data collection, data entry, or other reasons.

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Highly Correlated Attributes

Highly correlated attributes are variables in a dataset that have a strong relationship with each other.

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Descriptive Statistics

Descriptive statistics provide a summary of a dataset's key characteristics, including measures like mean, median, mode, standard deviation, and range.

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Univariate Exploration

Univariate exploration is a data exploration technique where you analyze a single variable at a time to understand its distribution, central tendency, and variability.

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Multivariate Exploration

Multivariate exploration is a data exploration technique that examines the relationships between multiple variables to understand how they influence each other.

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Iris dataset

The Iris dataset is a popular benchmark dataset used in data science for classification tasks. It contains measurements of sepal and petal lengths and widths for three species of Iris flowers.

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Sampling

The process of selecting a subset of records from a dataset to represent the whole dataset.

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Feature Selection

The process of identifying and selecting the most relevant attributes or features for a model.

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Model

An abstract representation of data and relationships in a dataset, often used for prediction or understanding.

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Descriptive Data Science

A type of data science technique that aims to understand patterns and relationships in data without a specific target variable.

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Predictive Data Science

A type of data science technique that aims to predict a specific target variable based on relationships in data.

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Curse of Dimensionality

The phenomenon where the performance of models can deteriorate as the number of attributes in a dataset increases.

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Correct Data Capture Outliers

Data captured correctly but representing unusual or extreme values.

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Erroneous Data Capture Outliers

Data captured incorrectly due to errors or mistakes.

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Correlation Coefficient (r)

A statistical measure that describes the strength and direction of the linear relationship between two variables.

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Positive Correlation

When two variables increase or decrease together, they have a positive correlation, and the correlation coefficient (r) will be close to 1.

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Negative Correlation

When one variable increases while the other decreases, they have a negative correlation, and the correlation coefficient (r) will be close to -1.

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No Correlation

If there is no linear relationship between two variables, the correlation coefficient (r) will be close to 0.

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Scatter Plot

A visual representation of data that helps us see the relationships between variables. It's like a picture that tells a story.

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Data Visualization

The process of using visuals to make sense of data. It's like using a map to navigate complex information.

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Univariate Visualization

Examining data one variable at a time, like looking at individual ingredients in a recipe.

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Multivariate Visualization

Examining data with two or more variables simultaneously, like looking at how different ingredients interact in a recipe.

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Study Notes

Introduction to Data Science

  • Dr. Amal Fouad is a Senior Data Scientist
  • Introduction to Data Science presentation

Agenda

  • Why study Data Science?
  • How Does Data Science Impact Organizations?
  • Application and Competitive Advantage
  • Importance of Data Science
  • What Will Be Discussed

DS vs AI vs ML vs DL?

  • Artificial Intelligence: Any technique that allows computers to mimic human behavior
  • Machine Learning: A subset of AI techniques that use statistical methods to enable machines to improve with experience
  • Deep Learning: A subset of Machine Learning that makes the computation of multi-layer neural networks feasible

DS vs AI vs ML vs DL? (Timeline)

  • Early Artificial Intelligence (1950s)
  • Machine Learning Flourishes (1990s-2000s)
  • Deep Learning Breakthroughs (2010s)

Why Data Science?

  • Information Created Worldwide: Expected to continuously accelerate, data is growing exponentially.
  • 2005 - 0.1 ZB of data
  • 2010 - 2 ZB of data (9%)
  • 2015 - 12 ZB of data (9%)
  • 2020 - 47 ZB of data (16%)
  • 2025 - 163 ZB of data (36%)
  • Data accumulating at 28% annual growth rate
  • Data Analysts in the workforce growing at 5.7% annual growth rate
  • Data Analyst shortage
  • Data is a huge field with lots of opportunities to study

Components of Data Science

  • Artificial Intelligence (AI): This is a broad field encompassing many techniques to mimic human behaviour
  • Machine Learning (ML): Methods used in AI to enable machines to learn from data
  • Deep Learning (DL): A specific technique of ML that involves networks of multiple layers
  • Maths & Statistics: Statistical models used for data analysis
  • Visualization: Using charts,graphs to visually present the data for better understanding
  • EDA (Exploratory Data Analysis): Process of discovering patterns in the data

Data Definition

  • Data is a collection of details, figures, symbols, descriptions
  • Raw data can be in various forms like letters, numbers, images, characters
  • Computer data is represented (in most cases) by a combination of 0's and 1's
  • Information is data to which meaning has been attached

Databases

  • Oracle
  • MySQL
  • Microsoft SQL Server
  • MongoDB
  • PostgreSQL

Data Definition (Databases aspect)

  • Databases are logical structures that rely on set theory, relationships between tables, and unique primary and foreign keys.
  • This keeps data integrity between tables
  • Data Science methods, processes and insight concerning structured or unstructured data

Data Science Definition

  • Data science is an interdisciplinary field that employs scientific methods, processes, algorithms, and systems to obtain knowledge and insights from structured or unstructured data.
  • Data Science is applied in many areas

Data Science Definition (Unified concepts)

  • Data science is a concept to unify statistics, data analysis, machine learning and their related methods.
  • Used for understanding and analyzing actual phenomena with the help of data
  • Drawn from mathematics, statistics, computer science, and information science

Data Science Definition (Roles & skills)

  • Analyst - Business administration. Exploratory Data Analysis.
  • Data Scientist - Advanced algorithms. Machine learning. Data preparation. Data governance. Data product engineering. SQL.
  • Data Engineer - Builds data pipelines.
  • Process Owner - Project management. Management of stakeholder expectations. Maintaining a vision. Facilitating processes

Data Scientist Starter Pack - Libraries

  • NumPy: A Python library for large, multi-dimensional arrays and matrices in order to use high-level mathematical numerical functions.
  • Scikit-learn: A free software library for classification, regression and clustering algorithms.
  • Pandas: A Python library for data manipulation and analysis of data structures.

Data Scientist Starter Pack - Tools

  • Jupyter: An open-source web application to create and share documents containing live code, equations, diagrams and narrative text.
  • Colab: similar to Jupyter Notebook but provides sharing and collaboration features.

Data Scientist Applications

  • E-commerce: Identifying customers, recommending products, analyzing reviews
  • Manufacturing: Predicting problems, monitoring systems, automating manufacturing units, maintenance scheduling, anomaly detection
  • Healthcare: Medical image analysis, drug discovery, bioinformatics, virtual assistants
  • Transport: Self-driving cars, enhanced driving experience, car monitoring system, enhancing passenger safety
  • Banking: Fraud detection. Credit risk modeling. Customer lifetime value
  • Finance: Customer segmentation, strategic decision making, algorithmic trading, risk analysis

Data Science - Importance

  • Data science helps brands to deeply understand their customers
  • Data science provides powerful and engaging ways for brands to communicate their story
  • The field of Big Data is a continuously evolving field

Data Science - Importance (Specific areas)

  • Data Science findings and results are applicable to sectors like travel, healthcare and education.
  • Data science is accessible to most sectors

Data Science Roadmap

  • Includes different areas of expertise, math, probability, statistics, programming, machine learning, deep learning, NLP, database, visualization tools, and deployment.
  • Includes project on various topics including credit card fraud detection, movie recommendation, data science at Netflix, data science at Flipkart

How YouTube uses AI

  • Automatically removes objectionable content
  • Recommends videos based on user choice
  • Organizes content

How Facebook uses AI

  • DeepText
  • Machine Translation
  • Automatic Image Recognition
  • Chatbots
  • Deepfakes
  • Targeted ads

How Google uses AI

  • DeepText
  • Gmail (smart replies, spam detection)
  • Google Search (suggestions based on past searches)
  • Google maps (ETA based on location, day of the week, trip time)
  • Google Translate
  • Speech Recognition

Companies using data science

  • Facebook
  • Amazon
  • Google
  • LinkedIn
  • Netflix
  • YouTube
  • Microsoft

Roles in Data Science

  • Data Scientist: Proves of disproves hypothesis. Gathering and wrangling data, develop and communicate

  • Data Engineer: Builds Data Driven Platforms, Operationalize algorithms, and handle data integration.

  • Data Analyst: Storytelling, build dashboards and other data visualizations. Providing insights through visuals

  • Process Owner Project management to maintain a vision for data that facilitates process

Learning Data Science with Python (Libraries)

  • NumPy: numerical computing library
  • Scikit-learn: machine learning library
  • Pandas: data manipulation and analysis library

Learning Data Science with Python (Tools)

  • Matplotlib: plotting library
  • TensorFlow: open-source library for dataflow programming. Used for machine learning, applications, and neural networks.
  • Keras: Neural network library that runs on TensorFlow
  • Jupyter: interactive computing environment
  • Colab: similar to Jupyter for collaborating and sharing

Data Science - Applications (List)

  • Consumer Identification
  • Product Recommendation
  • Review Analysis
  • Potential Problem Prediction
  • Automated Systems in Manufacturing
  • Maintenance Scheduling
  • Anomaly Detection
  • Fraud Detection
  • Credit Risk Modeling
  • Customer Lifetime Value
  • Medical Image Analysis
  • Drug Discovery
  • Bioinformatics
  • Virtual Assistants
  • Self Driving Cars
  • Enhanced Driving Experience
  • Car Monitoring System
  • Improving Passenger Safety
  • Customer Segmentation
  • Strategic Decision Making
  • Algorithmic Trading
  • Risk Analysis

Data Science - Additional key definitions

  • Data is a collection of details and facts.
  • Information is derived from processed data.
  • Analytics are methods to get insight from data
  • Data Science is an interdisciplinary field
  • AI is mimicking human behavior
  • Machine Learning enables machines to learn
  • Deep learning uses multiple layer neural networks

Data Cleaning

  • Incomplete data
  • Noisy data
  • Inconsistent data

Handling Missing Values

  • Replace with default values
  • Calculate mean/mode, and fill in missing numerical/categorical fields respectively
  • Generate random values from existing data distribution (as needed)

Handling Outliers

  • Data Values that exceed expected values.
  • Potentially due to erroneous data processing errors
  • Remove or adjust the values
  • Check data for consistency

Handling Noisy Data

  • Errors in Data collection, entry, transmission or technology limitations.
  • Data validation and correction process is used for fixing errors

Handling Inconsistent Data

  • Data values that differ from expected values
  • Use data dependencies to detect and rectify inconsistencies

Data Science Process

  • Understanding the problem
  • Prepare data samples
  • Develop a model
  • Apply model to dataset
  • Deploy, maintain models

Prior Knowledge

  • Understand the objective of the problem being investigated
  • Understand subject matter
  • Understand the data context

Data Preparation

  • Data exploration (to understand the data characteristics)
  • Handling data quality (validating or fixing erroneous data)
  • Handling missing data (managing or replacing missing values)
  • Data type conversion (converting between different data types, if necessary)
  • Handling data anomalies (handling outliers or highly correlated attributes)
  • Feature Selection (Selecting relevant/important features from large datasets)
  • Sampling (Representing a sample from a dataset)

Data Modeling

  • Creating a model that provides representation of data and relationships within context
  • Making predictions based on a trained model

Data Application

  • Assimilation of model results into the business process
  • Deployment and maintenance of the model

Data Visualization

  • Visualizing data helps to identify trends & correlations in data
  • Univariate visualization (analyzing one attribute at a time)
  • Multivariate Visualization (analyzing multiple attributes together)
  • Charts can display trends and relationships.
  • Graphs can help in interpreting trends and patterns from the data effectively

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