Monday, May 17, 2010

Old School Rules: A Normal Slide Rule


Here's a normal slide rule. Yes, it's very old technology, but it helps to see some workings that other high-tech black boxes hide.
Of course you can even get much more extensive stat calculators for your IPhone See StatsMate. Still this is fun.


Find the BIG TIF file at this link (or click on the illustration below). And, as requested, here is a smaller pdf version. Print it out on heavy card stock.


Cut off the slider on the left and set it aside. On remaining front section, cut out the normal curve and the results window. Fold back the top and bottom. Then slide in the slider with the numbers down and the blue rectangle up.
Pick your z-score and read the area of the blue shaded region.

7 comments:

red dave said...

That is brilliant. Great post.
On a similar note have you seen the slide rule nuclear bomb effects computers?
http://liveatthewitchtrials.blogspot.com/2009/02/madness.html

Robert W. Jernigan said...

Thanks for the kind words and the link.

Efrique said...

Very interesting.

But...

According to Firefox that tif file is a little under 200*MB*.

Not 200 KB.

BIG difference.

200MB seems a little unnecessary for this 1 page image.

Is there a version that's not quite so freaking big?

Dr.J. said...

Yes, it is just under 200MB. Sorry for the confusion. I've called it BIG. Perhaps a smaller one someday.

Robert W. Jernigan said...

A smaller pdf version of the normal slide rule is now posted.

Efrique said...

Thanks very much for going to the trouble! Much appreciated.

Edgar said...

Try this command:

convert NormalRule004.tif -resize 50% -quality 85 NormalRule004.jpg

This will reduce the file size by 99.67% with no noticeable loss of quality.