## Wikipedia is useless

...at least sometimes it is. Take this gem, for example:

In probability theory and statistics, the probit function is the inverse cumulative distribution function (CDF), or quantile function associated with the standard normal distribution. It has applications in exploratory statistical graphics and specialized regression modeling of binary response variables.

A well-trained statistician will be perfectly able to understand the above, and perhaps fix any errors in it. However, anyone who isn't a highly trained statistician will not; and a trained statistician probably doesn't even need wikipedia to know the above.

I did get some basic statistics during my last studies, and have an understanding of some of the basic terms and concepts of statistics. Yet the above makes no sense to me, at all.

As an example, consider the familiar fact that the N(0,1) distribution places 95% of probability between -1.96 and 1.96, and is symmetric around zero. It follows that

$\Phi(-1.96) = 0.025 = 1-\Phi(1.96).\,\!$

... Or something. Suuuure.

(posted belatedly because my server was down yesterday)