Normal Distribution - Guide 5, p. 91

[rheyn]

Hey to everyone from Michigan!

As I am just sitting over "The Normal Distribution", I wonder whether there might be a mistake in my guide, probably copy-and-pastish or so.

On page 91, Gd. 5, the 2/3 example for the normal distribution explains:

Roughly 2/3 of the example will fall within 1 standard deviation of the mean. Thus in the above example, a value of 6 is at roughly 50% - 50% - (1/2)(2/3) = 17% ≈ 17%, or the 17th Percentile. A value of 14 is at roughly 50% + 50% - (1/2)(2/3) = 17% = 83%, or the 83rd Percentile.

Well, I am sitting in front of my desk and I simply don't catch it as it is written. However, 50% - (1/2)(2/3) = 17% and 50% + (1/2)(2/3) = 83% would make sense.

[tommywallach]

Hey Rheyn,

Yep, looks like a typo. You can see the math explaining two standard deviation math just below it, and see what it ought to be (as you described). I've forwarded to our errata team.

Just FYI, the other thing pointed out as a typo in another post was not one! We try to keep up with errata as much as possible, and this is our first guide since the revised edition, so a few kinks are still being ironed out. Always let us know when you think you've found something.

Thanks!

-t