Stratification in Excel with real life example

This video is about practical guide for stratification in excel. This is the first and very important step of data analysis.
WHAT IS STRATIFICATION?
Stratification is defined as the act of sorting data, people, and objects into distinct groups or layers. It is a technique used in combination with other data analysis tools.
When data from a variety of sources or categories have been lumped together, the meaning of the data can be difficult to see. This data collection and analysis technique separates the data so that patterns can be seen and is considered one of the seven basic quality tools.
WHEN TO USE STRATIFICATION
Before collecting data
When data come from several sources or conditions, such as shifts, days of the week, suppliers, or population groups
When data analysis may require separating different sources or conditions
Here are examples of different sources that might require data to be stratified:
Equipment
Shifts
Departments
Materials
Suppliers
Day of the week
Time of day
Products