Can statistics be used to improve human-computer interaction?
Of course!
I think it's common knowledge that the QWERTY layout that most of us use is the way it is because it was an optimal layout for typewriters. Keys were ordered in such a way as to reduce the hammers of common characters jamming.
Only today, we don't have hammers. Nor ink spools. (Nor the smell of oil after you've been typing for half an hour!)
So why do we still have QWERTY? Is there a statistically better key layout for humans now that we don't have to worry about typewriter hammers jamming?
YES.
I've started trying to relearn how to type using a layout called Colemak-DH.
Thinking in terms of touch-typing, where your fingers rest on the home row; in QWERTY, 32% of typing is done on the home row. In Colemak, 74% of typing is done on the home row. (ref: Wikipedia)
I like those numbers!
The Colemak-DH layout arguably improves upon Colemak. It reduces horizontal finger movement by changing the center column of keys further: Colemak center column usage being 14.8% while Colemak-DH is 7.8%. Big reduction. (ref: Mod-DH)
One last thing that always confused me. If you're typing on a QWERTY keyboard, have a look at the "Q", "A" and "Z" on the left hand side. They're positioned diagonally... though not perfectly. The "A" is about a third of a key along to the right, then the "Z" is two thirds away from the "A" (The "Z" isn't vertically aligned with the "Q" at all!). I can't help but think my typing inaccuracy on QWERTY has frequently been caused by this inconsistent horizontal shift. But turns out there's a way I can test this! These days you can buy ortholinear keyboards. Keyboards that have their keys arranged directly above and below each other. Some good examples here so you can see what I mean.
So I decided to take the dive. Let's look at two keyboards that give me the flexibility to type how I want!
So in future I'll be typing a little bit about what it is to relearn how to type.
is an unbiased estimator of the population variation 
as shown below:![\[<span class="ql-right-eqno"> </span><span class="ql-left-eqno"> </span><img src="https://adrianbell.me/wp-content/ql-cache/quicklatex.com-8309d8e21d5c74b4a21588f648103d5a_l3.png" height="45" width="261" class="ql-img-displayed-equation quicklatex-auto-format" alt="\begin{align*} E(s^2) =& E \left( \frac{ \sum_{i=1}^n( x_i - \bar{x} )^2 }{n-1}\right) = \sigma^2 \end{align*}" title="Rendered by QuickLaTeX.com"/>\]](https://adrianbell.me/wp-content/ql-cache/quicklatex.com-8a7d43be7fd6e7be52bea4f0d920ad7d_l3.png "Rendered by QuickLaTeX.com")
" divisor? Check out the full explanation