TITLE: notation of distribution
QUESTION [5 upvotes]: I have a question: 

Does  $$N(0, x)$$ mean a normal distribution with mean $0$ and variance $x$? Or standard deviation $x$?

The notation seems ambiguous sometimes.

REPLY [3 votes]: This question came up on stats.SE as well.  Apparently, there
are three different conventions in use in the statistical 
literature, and for $x$ in $N(0,x)$ to mean standard deviation $\sigma$
is quite common (I am told Wolfram Alpha uses this convention,
to answer a question from @MichaelHardy).  What is more interesting
is a comment on this question
on Stats.SE which says that $x$ can even mean $1/\sigma^2$ in
Bayesian contexts. 
This answer summarizes
the discussion on stats.SE.