Course-3 Prepare data for explorations Flashcards
Prepare Phase
1) Understanding the different types of data and data structures.
2) What type of data is suitable for the question you answering?
3) Practical skills in extracting, organising and protecting your data.
4) How data is generated and collected.
5) Different formats, types, and structures of data.
How is data collected?
1) Interviews
2) Observations
3) Forms
4) Questionnaires
5) Surveys
6) Cookies
Data collection considerations
1) How will the data be collected
2) Choose data sources
3) decide what data to use
4) How much data to collect
5) Select the correct data type
6) Determine the time frame
First-party data
Data is collected by an individual or group using their resources.
Second-party data
Data collected by a group directly from its audience and then sold
Third-party data
Data was collected from outside sources who did not collect it directly.
Population
All possible data values in a certain dataset.
Sample
A part of a population that is representative of the people.
Discrete data
Data that is counted and has a limited number of values.
Continuous data
Data that is measured and can have almost any numeric value.
Nominal data
A type of qualitative data that is categorized without a set order.
Ordinal data
A type of qualitative data with a set order or scale.
Internal data
Data that lives within a company’s own systems
External data
Data that lives and is generated outside of an organisation.
Structured data
Data is organised in a specific format, such as rows and columns.
Examples of software that store structured data.
Spreadsheets, Relational databases
Unstructured data
Data that is not organised in any easily identifiable manner
Examples of unstructured data
Audio files, Video files
Primary data
Collected by a researcher from first-hand sources.
Example of primary data
Data from an interview you conducted
Secondary data
Gathered by other people or from further research.
Example of secondary data
demographic data collected by a university
Internal data
Data that lives inside a company’s own systems
example of internal data
Sales data by store location.
External data
Data that lives outside of a company or organisation
example of external data
National average wages for t he various positions throughout your organisation.
Continuous data
Data that is measured and can have almost any numeric value
Continuous data example
1) Temperature
2) Runtime markers in a video
Discrete data
Data that is counted and has a limited number of values.
Example of discrete data
Number of people who visit a hosptal on a daily basis (10,20,200)
Qualitative data
Subjective and explanatory measures of qualities and characteristics.
Example Qualitative data
Excercise activity most enjoyed
Quantitative data
Specfic and objective measures of numerical facts
Quantitative data example
Population of elephants in Africa
Nominal data
A type of qualitative data that isn’t categorized with a set order,
Nominal data example
New listing, reduced price listing, foreclosure.
Ordinal data
A type of qualitative data with a set order or scale.
Ordinal data example
Income level ( low income, middle income, high income)
Structured data
Data is organised in a specific format, like rows and columns.
structured data example
Expense reports
Unstructured data
Data that isn’t organised in any easily identifiable manner.
Unstructured data example
- Social media posts
- Emails
- Videos
Data Model
A model that is used for organising data elements and how they relate to one another.
Data elements
Pieces of information, such as people’s names, account numbers, and addresses.
Sources of structured data
1) Spreadsheets
2) Databases that store datasets
Data modelling
Data modelling is creating diagrams visually representing how data is organised and structured.
Levels of data modelling
1) Conceptual ( Business concepts)
2) Logical ( Data entities)
3) Physical ( Physical tables)
Conceptual data modelling
Conceptual data modelling gives a high- view of the data structure, such as how data interacts across an organisation.
Example Conceptual data modelling
A conceptual data model may be used to define the business requirement for a new database. A conceptual data model doesn’t contain technical details.
Logical data modelling
Logical data modelling focuses on the technical details of a database, such as relationships, attributes, and entities.
Logical data modelling example
For example, a logical data model defines how individual records are uniquely identified in a database. But it doesn’t spell out the actual names of database tables. That’s the job of a physical data model.