This video, Null Hypothesis, is the first of hopefully many videos based on content from the book, Statistics from A to Z -- Confusing Concepts Clarified. They will be on the YouTube channel which has the same name as the book here's a link http://bit.ly/2dD5H5f. Please subscribe to the channel to be notified when new videos are uploaded. You can also see on the Videos page on this website not only which videos are currently available, but also which are planned to be uploaded next.
As you can see from the graphic above, the videos, like the articles in the book, usually start with 4 or 5 Keys to Understanding (KTUs), so that you can see on one page the key things you need to know to understand the concept. The rest of the article or video goes into detailed explanations of each KTU.
This little cartoon is used in support of KTU #2. I've found it's usually best to try to phrase the Null Hypothesis as either no difference, no change, or no effect.
However, it's even clearer to avoid the use of words completely, as KTU #3 explains.
Andrew A. (Andy) Jawlik is the author of the book, Statistics from A to Z -- Confusing Concepts Clarified, published by Wiley.