What is PCA? PCA is fundamentally a dimensionality reduction algorithm, but it can also be useful as a tool for visualization, for noise...

Description The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id. The...

Description The Employee table holds all employees. Every employee has an Id, and there is also a column for the department Id. The...

Description Write a SQL query to find all numbers that appear at least three times consecutively. [Read Full Description Here] Solution...

Description Write a SQL query to rank scores. If there is a tie between two scores, both should have the same ranking. Note that after a...

Description Write a SQL query to get the nth highest salary from the Employee table. For example, given the above Employee table, the nth...

Database Description: The Trips table holds all taxi trips. Each trip has a unique Id, while Client_Id and Driver_Id are both foreign...

Survival Analysis is time to event analysis. Time to event is the time it takes until a pre-defined event occurs. The times till events...

This is about comparing the survival experience between categorical explanatory variable. For example, we may wish to see if gender has...

Conjoint analysis is a technique for measuring, analyzing, and predicting customers’ responses to new products and to new features of...