Correlation and causation
You may have heard the phrase ‘correlation does not imply causation’ or ‘correlation is not causation’, but what does this mean? Earlier, you saw how two variables can be correlated, …
Course: SQL for Data Analysis
Optional Project Task: Start diagnosing your data
If you are completing the optional project for this course, you may have already prepared your data as part of the second round of exploratory analysis in Course 2. To …
What is Querying a Database?
Querying a database involves requesting to access data from a database to retrieve it or manipulate it. The SELECT statement is the most commonly used SQL statement for querying data …
Database fundamentals
As an analyst you’ll often work with databases, especially when you have to analyse business data or transactions. This video covers the basic information about databases that you must know …
Introduction to SQL
Structured Query Language (SQL) is the most widely implemented database query language and is supported by many popular relational database systems, including: MS SQL Server, IBM DB2, MySQL, and Microsoft …
SQLite: How to Create a Database Using DB Browser
We are going to demonstrate how to create a database using DB browser. This will be a blank canvas to create table structures, which we’ll fill with information. Using DB …
Calculating correlation with spreadsheets
To calculate the correlation in an Excel spreadsheet, you can use the CORREL() function. Let’s look at an example. Consider these two lists of data in an Excel spreadsheet: To …
How to Filter Query Results in SQL
Being able to retrieve a set of columns from a database is useful, but we don’t really begin to leverage the power of SQL until we start to filter specific …
Diagnostic techniques
Any diagnostic technique’s main purpose is basically to discover the root cause of the problem or event you have discovered. There are a few methods that can be employed in …
Pearson’s correlation coefficient
Pearson’s correlation coefficient ((r)) is used to describe the correlation between two variables with a linear relationship. (r) varies from -1 to +1, where: -1 represents a strong, negative correlation …