Q:

strange bug in numbering

In this question, we see a list of three hypotheses numbered 1, 2, and 3, but when I click on "edit", they're numbered 2, 3, and 4, and the question refers at one point to 4.  When reading rather than editing, one doesn't see any "4".
BEGIN QUOTE
My professor asked this question 
Why is the hypothesis test correct 

$H_0: \mu_1=\mu_2=\mu_3$

$H_a:$ at least one different 
And these hypothesis wrong

$H_0: \mu_1=\mu_2$ 
$H_0: \mu_2=\mu_3$,
$H_0: \mu_1=\mu_3$

So basically why cant we say that if we reject 2, 3, and 4 than why cant we reject 1 or if we reject 2, 3, or 4 than we can reject 1? He basically wants to know why we must use the first hypothesis test and not the last three?
END QUOTE

A:

Actually, lists are handled automatically. I can number them however I want, but the parser will make them all nice, like

This is actually labelled 17 in the source
This is labelled 11
This is labelled 10
This is part of Markdown, and as far as I know, there is no intention of it changing. 
But one way to continue the list is to include 2 spaces at the start of middle lines. This is an example of an extended option 3.
Then at the end of the day, you just resume numbering. (Plot twist - this actually is labelled  4 - but it doesn't need to be).

Conceivably, SE could start to allow people to use ordered lists via HTML, but this isn't currently done. In fact, it currently looks really funny.
<ol type="I">
<li>testing</li> 
<li>hmm</li>
</ol>

yields
testing
hmm
which is an ordered list, but which is not prefaced by capital Roman numerals.

