Skip to main content
Cross Validated

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

5
  • 3
    $\begingroup$ Michael, because "<" and ">" have special meanings on Web pages, to avoid having large swathes of your text simply disappear from view you it is essential that you use $\TeX$ markup for them in equations (the codes are "\lt" and "\gt" respectively). I marked up the two equations that caused this problem for you. In the future, please read what you post immediately after posting it to make sure people are seeing what you thought they would see, and then feel free to flag your post for moderator attention if there is some problem with the markup. $\endgroup$ Commented Sep 27, 2012 at 16:28
  • $\begingroup$ @whuber Thank you. I generally do check during and after posting because I find that I mess up equations a lot especially when subscripting. Missing this one is unusual and probably happened because it was a long post and I just carelessly went on to something else that I wanted or needed to do. Sometimes a phone call distracts me and I forget to check. Regarding special symbols that cause text to disappear in a post, I have observed that. I think a simple solution is to make sure you leave a space after the symbol. I think that has worked for me in the past. $\endgroup$ Commented Sep 27, 2012 at 16:38
  • $\begingroup$ +1, really on-point. Note that if $X$ & $Y$ are perfectly uncorrelated in your sample, $\text{Var}(Z)=\text{Var}(X)+\text{Var}(Y)$. $\endgroup$ Commented Aug 23, 2013 at 3:23
  • $\begingroup$ @MichaelChernick For the case when Cov(X,Y)<0, I have a question: If my goal is to infer E[X]-E[Y] from my experiment, then EVEN THOUGH I conducted a paired study, when I analyze my data, I can still PRETEND that my experiment result is a realization of UNPAIRED randomized experiment. Can I do this? Because if you truly did an unpaired random experiment, you can literal get the same outcome. Then I can just take the average of each group (ignore the pairing stuff) and take the difference of the two group mean. This is an unbiased estimator of E[Z]. For variance of my estimator, I just use... $\endgroup$ Commented Mar 8, 2018 at 3:49
  • $\begingroup$ @MichaelChernick the sample variance of group X and group Y and sum them up $\endgroup$ Commented Mar 8, 2018 at 3:49