Data Science Fundamentals

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Questions and Answers

What defines a symmetric binary variable?

Both choices have equal importance. (correct)

Options can vary in probability.

One choice is always more important than the other.

It consists of three or more choices.

Which of the following is true regarding ordinal data?

Relational operators can't be applied to ordinal data.

Ordinal data can reflect a ranking of items. (correct)

It always has numerical values.

Ordinal data cannot be ranked.

What is an example of an asymmetric binary variable?

Age categories

Color choices

Medical test results (correct)

Gender

Which operation is typically NOT permitted on ordinal data?

Performing addition Signup and view all the answers

Which statement is accurate regarding the transformation of variables between numeric and ordinal?

Transforming from numeric to ordinal results in a loss of information. Signup and view all the answers

What type of measurement includes categories without any inherent order?

Nominal scale Signup and view all the answers

Which scale of measurement allows for both order and a measurable difference between values?

Interval scale Signup and view all the answers

Which of the following is an example of document data?

Term-frequency vector Signup and view all the answers

In the NOIR classification, which scale indicates variables that have a true zero point?

Ratio scale Signup and view all the answers

What characterizes binary data in the context of the NOIR classification?

It consists of two distinct categories Signup and view all the answers

Which of the following statements is true about quantitative data?

It can be ordered and have measurable differences Signup and view all the answers

What best describes the properties of categorical data?

They have distinct categories that can be counted Signup and view all the answers

Which type of data is exemplified by a numerical matrix in research?

Record data Signup and view all the answers

What is a characteristic of a nominal variable?

It is used to categorize data without a logical sequence. Signup and view all the answers

Which of the following is an example of a binary variable?

Gender represented as Male and Female Signup and view all the answers

What does the nominal scale primarily do?

Labels categories without an order. Signup and view all the answers

Which of the following statements is true about nominal data?

Labels can be identical or dissimilar. Signup and view all the answers

Why can mathematical operations not be performed on nominal data?

Nominal data represents categorical variables without inherent values. Signup and view all the answers

In the context of variable types, what distinguishes a binary variable?

It represents exactly two mutually exclusive categories. Signup and view all the answers

Which of the following is a potential misuse of nominal data?

Trying to rank categories. Signup and view all the answers

What is the defining feature of nominal data types?

They can be expressed in numeric form. Signup and view all the answers

What is a characteristic of interval data?

It has equal intervals between values. Signup and view all the answers

Which of the following types of data does not possess a true zero?

Interval data Signup and view all the answers

What type of operation can be performed on interval data?

Addition and negation Signup and view all the answers

Which statement best describes discrete data?

It can only take specific individual values. Signup and view all the answers

Which of the following best exemplifies ratio data?

Age of a person Signup and view all the answers

What is the main difference between continuous and discrete data?

Continuous data can take any value, while discrete data is countable. Signup and view all the answers

Which category does 'temperature in Fahrenheit' fall under?

Interval data Signup and view all the answers

Which of the following is NOT true about operations on interval data?

Only linear transformations can be applied. Signup and view all the answers

Study Notes

Attendance

Mark attendance within a minute.

Data in Data Science

Entity: A particular thing.
Attribute: Measurable/observable property of an entity.
Data: A measurement of an attribute.
Computers can manage various data types (audio, video, text, etc.).

Data Categorization

NOIR: Nominal, Ordinal, Interval, Ratio
Classification scheme for data types.

Types of Datasets (1): Record Data

Relational records: Database tables with highly structured data.
- Example tables: "Person" (Pers_ID, Surname, First_Name, City) and "Car" (Car_ID, Model, Year, Value, Pers_ID).
Data matrix: Numerical matrix, crosstabs. Example includes a table of sales data organized by region/product.
Transaction data: Example includes a table detailing orders with items and unique order IDs.
Document data: Term-frequency vector/matrix describing text documents. Example includes a table listing documents with counts/frequencies of words like "team" or "coach".

Types of Datasets (2): Graphs and Networks

Transportation networks: Maps of transportation routes.
World Wide Web: Network of interconnected webpages.
Molecular structures: Network of atoms.
Social or information networks: Relationships between entities.

Nominal Scale

Definition: A variable with values from a set of mutually exclusive codes with no logical order.
Example Codes: Gender (M, F); Blood groups (A, B, AB, O); Country code (048, 040).
Note: The variable can be numbers, letters, strings in label format. The number of categories should be finite and mutually exclusive.
Note: Numerical values don't have mathematical meaning.
Important: Values can't be ordered. (A != B, but A=A).

Binary Scale

Definition: A special case of nominal scale with two mutually exclusive categories (e.g., ON/OFF, True/False).
Example: Switch status, attendance (Yes/No).
Note: A binary variable is only two values.

Symmetric and Asymmetric Binary Scales

Symmetric: Binary choices have equal importance, e.g., Gender.
Asymmetric: Binary choices have unequal importance, e.g., medical test outcome (covid positive/negative).

Ordinal Scale

Definition: Ordered nominal data; the variable generates ordered data.
Example: Shirt size (S, M, L, XL, XXL).
Note: Values can be ordered; use relational operators ( <, >, =).

Interval Scale

Definition: Data measured on a numerical scale with equal intervals between adjacent values.
Example: Temperature (Celsius, Fahrenheit), IQ scores.
Note: An interval scale does not have a true zero.

Ratio Scale

Definition: Data measured on a numerical scale with equal intervals and a true zero.
Example: Weight (kg), Income (USD),
Note: All arithmetic operations (addition, subtraction, multiplication, division) are permissible.

Operations on Data

Distinctiveness: Data values are distinct.
Order: Data values are ordered.
Addition: Data values can be added.
Multiplication: Data values can be multiplied.

Continuous and Discrete Data

Discrete: Data can only take on certain individual values, e.g., the number of pages in a book.
Continuous: Data can take on any value within a certain range, e.g., the length of a film.

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Description

This quiz covers essential concepts in data science, including data types and categorizations. It explores the different types of datasets and how computers manage various data forms, from relational to transaction data. Test your understanding of key terms and definitions in this important field.