The DQYDJ Weekender, 7/14/2012

August 22nd, 2020 by 
PK

Welcome Len Penzo Readers!

It's a person and a site.  If you have no idea what I'm talking about, click here.

For the record, I fixed the sprinkler pipe.  I used the "4 90 degree angle" method since I don't trust those expanding sleeves.  Good thing none of you will ever see it.  Also, I received some traps this morning.  More on that story later!

What Kind of Math is That?

Always looking to have something funny to rag on Cameron about, I read this article about simple errors made by lots of Economists.  Let's play along and see if an Engineer makes the same errors.  (For the working paper, click here)

The question?  At what value of X do you have a 95% chance of a positive value of Y.  (A dot in positive territory).  Now, Felix Salmon, the author, said the answer was 47.  For standard error, a 90% confidence interval (namely 5% of points will fall above the interval and 5% below) means you multiply the standard error by 1.645.  1.645*29 = 47.705, not 47.  The first integer which has 'positive odds' of 95% is 48, not 47.

Seriously, what am I missing here?  How did so many people guess weird numbers?  Signed, an Engineer.

Links to Us!

Articles We Liked!

Go read Len's site for this week.  A new collection in just 7 days!

Politics!  Got Your Politics Here!

Look to the right and you'll see a new status indicator tracking 2012 election odds.  Every 15 minutes it will ping InTrade and pick up the currently trades odds for Senate and House control, as well as President.

Hope you enjoy it!  If you don't, deal with it - at least through November.  And, of course, if you want to add something similar to your site mail me and I'll help you out (same goes for the other scripts I've written).

      

PK

PK started DQYDJ in 2009 to research and discuss finance and investing and help answer financial questions. He's expanded DQYDJ to build visualizations, calculators, and interactive tools.

PK lives in New Hampshire with his wife, kids, and dog.

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