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Bounds represent the points with which data cannot exceed, such as minima or maxima.

7 votes
Accepted

If $\text{Var}(X) < \infty$, is $\text{Var}(XY) < \infty$ for $0 \le Y \le 1$?

I've unaccepted kjetil's answer since, as was pointed out in the comments, it assumes $X$ and $Y$ are independent. The following answer should work when $X$ and $Y$ are dependent, by using whuber's s …
Aaron Voelker's user avatar
7 votes
2 answers
298 views

If $\text{Var}(X) < \infty$, is $\text{Var}(XY) < \infty$ for $0 \le Y \le 1$?

I have a variable $X$ that I know has finite variance (and therefore also finite mean). Is it always true that its variance remains finite after scaling by $0 \le Y \le 1$? Note that $X$ and $Y$ are …
Aaron Voelker's user avatar