[wald_friedman] Add lecture once `jupytext` issue sorted out

[mmcky]

The conversion to ipynb using jupytext has an issue with the following block quotes when they are both in the same file. They work individually!.

> The standard statistical answer was to specify a number of firings (say
> 1,000) and a pair of percentages (e.g., 53% and 47%) and tell the client
> that if A receives a 1 in more than 53% of the firings, it can be
> regarded as superior; if it receives a 1 in fewer than 47%, B can be
> regarded as superior; if the percentage is between 47% and 53%, neither
> can be so regarded.

> When Allen Wallis was discussing such a problem with (Navy) Captain
> Garret L. Schyler, the captain objected that such a test, to quote from
> Allen's account, may prove wasteful. If a wise and seasoned ordnance
> officer like Schyler were on the premises, he would see after the first
> few thousand or even few hundred [rounds] that the experiment need not
> be completed either because the new method is obviously inferior or
> because it is obviously superior beyond what was hoped for
> $\ldots$.

[mmcky]

There is still an issue with double newlines at the end of the file -- so need to keep that in mind if updating from lecture-python.

Added it back in.