I get it, its a pretty hard sell to get people to buy a book about equations. But when you write a book called In Pursuit of the Unknown: 17 Equations That Changed the World, it might be a good idea to get the equations right. Math is hard, but it's not that hard. Chapter 7 covers the equation for the standard normal distribution. Here is the offending equation from page 107:

Also, it is repeated wrong on page 115:

There are lots of ways to write this equation, as far as being algebraically equivalent. However, what you see above is not it. Here is the corrected version.

Seriously, I teach this in high school. It's not that hard.