It is my experience that there are a lot of UX practioners out there who dont know the ISO definition
It is important to know the ISO definition of usability in order to be able to measure it
The three important and measurable items from the definition
The three important and measurable items from the definition
When you understand this joke, then you know enough about statistics
Standard deviation:
1=68%
2=95%
3=99.7%
Some are proprietary
Let have a closer look at some of them