Feb 26, 2013

Humor: Actuarial Creativity

As actuaries we've studied a lot in life. And to keep up with actuarial science we'll probably keep studying until our personal mortality rate hits us finally in the back.

Although study brought us to the top of financial and statistic modeling, there's a small but fatal risk that we become so engrossed in our work that we loose our creativity or ability to solve things in a simple way.

Test

To test whether you're still a creative 'simplist', let's do a short 3 question test. Here it is:

Question 1
 "Show how it is possible to determine the height of a tall building with the aid of a barometer."



If you think you've solved this high school level problem, go to the next question

Question 2
 "Solve question 1 with another method."

If you think you've solved this problem as wel, go to the final question

Question 3
 "Solve question 1 with 4 other methods."

Evaluation
Although actuaries never give up, there's a slight chance you had to surrender and are longing for the answer.
In that case (only), read further for the answer.

Answer: The Barometer Fable
Bob Pease (Nat.Semi.) records the story of the Physics student who got the following question in an exam: "You are given an accurate barometer, how would you use it to determine the height of a skyscraper ?"

  1. He answered: "Go to the top floor, tie a long piece of string to the barometer, let it down 'till it touches the ground and measure the length of the string".

    The examiner wasn't satisfied, so they decided to interview the guy: "Can you give us another method, one which demonstrates your knowledge of Physics ?"
     
  2.  "Sure, go to the top floor, drop the barometer off, and measure how long before it hits the ground……"

    "Not, quite what we wanted, care to try again ?"
     
  3. "Make a pendulum of the barometer, measure its period at the bottom, then measure its period at the top……"

    "..another try ?…."
     
  4. "Measure the length of the barometer, then mount it vertically on the ground on a sunny day and measure its shadow, measure the shadow of the skyscraper….."

    "….and again ?…."
     
  5. "walk up the stairs and use the barometer as a ruler to measure the height of the walls in the stairwells."

    "…One more try ?"
     
  6. "Find where the janitor lives, knock on his door and say
    'Please, Mr Janitor, if I give you this nice Barometer, will you tell me the height of this building ?"


Find more than 140 solutions and read the original famous Barometer Fable, as published in 1968 in an article  by Alexander Calandra.

Warning!
Keep in mind that not every method leads to satisfactory results.
An uncertainty analysis of determining a building height using a barometer, developed by Israel Urieli, shows that this method is not accurate at all!

So the surprising news is that the first two alternative methods mentioned above are more accurate than the method you learn at high school.

Finally
It's always best when you can solve an (actuarial) problem in more than one way and the outcomes point in the same direction. The more a specific solution comes to front by applying different methods and/or data, the more confident you can be that the outcome is robust.

Used Sources

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