You are not alone if you are confused by statistics #5

I don't know what mathematicians think.  But I have been struck by inconsistencies in terminology and by disagreement about fundamental concepts among experts in statistics. 

For example, I was watching a video in which a professor kept mentioning "scatter". I had no idea what he was talking about, but eventually it became clear that "scatter" was the same thing as "variation" -- which is also known as "variability", "dispersion", and "spread". That's 5 terms for one concept.

Here's another example: in the equation y = f(x), y is variously known as the 

• y variable
• dependent variable
• outcome variable
• response variable
• criterion variable
• effect

Also, "SST" is the usual abbreviation for Sum of Squares Total. And 
SST = SSR (Sum of Squares Regression) + SSE (Sum of Squares Error)
But one author (at least) uses "SST" (Sum of Squares Treatment) instead of "SSR" -- which is very confusing. (I forget what they renamed Sum of Squares Total.)

And experts disagree about some very basic concepts. For example:

• ​Some include stating the Alternative Hypothesis as a standard step in Hypothesis Testing. Others are "vehemently opposed" to its use.
• Most insist that you must say "Fail to Reject" the Null Hypothesis. But some say that it's OK to "Accept" the Null Hypothesis.
• And it seems generally accepted that overlapping Confidence Intervals means that there is no statistically significant difference. But some experts say that there can be an overlap of as much as 20% with a statistically significant difference.