Help with understanding point from Nassim Taleb's book "Dynamic Hedging"

Question

This is an excerpt from Nassim Taleb's book "Dynamic Hedging" (a book on option trading strategies) page vii

Most examples in this book are presented as generic situations. The volatility will be defined as 15.7% (to make one standard deviation equal to 1% daily move).

I'm trying to understand where the numbers 15.7% and 1% came from. How were they derived or estimated?

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Edit: Adding more context, here's a screen cap of the actual text:

Answer 1

With a 248 day year, use $\sigma \sqrt{\frac{1}{248}} =.01$ to normalize for a daily $\sigma$ of $1\%$. This gives $\sigma \approx .157$.