Yes, that's it. And it's used to eliminate bias. I found a good explanation at https://www.youtube.com/watch?v=xquB4rDbsvc https://www.youtube.com/watch?v=xqu

Yes, that's it. And it's used to eliminate bias. I found a good explanation at https://www.youtube.com/watch?v=xquB4rDbsvc https://www.youtube.com/watch?v=xquB4rDbsvc at about 14min.