Friday, October 16, 2015

Recognizing number patterns and probabilities

Years ago when I delivered newspapers,  I learned about street numbers and apartment numbers.  And I remember when old mail routes were renumbered so the emergency personnel could find each residence.  I guess not everyone got the memo.  Several weeks ago I had the occasion to call the sheriff's department.  It was after dark, and I told the deputy my address and promised to leave my porch light on.  I live in a subdivision and the house number pattern is straightforward:  sequential even numbers on the right and sequential odd numbers on the left.  Now what is the probability that the deputy goes to the wrong house (even though I was the only one with a porch light on).  Quite a few of the neighbors have numbers on their mailboxes and/or houses.  The deputy pointed out that I didn't have a number on my house.  "It's on the mailbox," I replied.  Of course, I noticed later that a morning glory vine has mostly obscured the number.  Still, no excuse for a deputy to go to a house on the right when the odd numbered houses are on the left. 
Then yesterday, I encountered another person who was thrown off by a simple number pattern.  First, some background--I don't clean windows often, but I had taken a notion yesterday to clean the windows of the front storm door.  It's also not very often that someone rings my doorbell, either.  Now what are the chances that I will be in the bathroom when someone does?  Yes, I was in the bathroom when the doorbell rang.  I got to the door as quickly as possible to find a lady with a pizza.  She needed to be at the house next door.  Then, after she left I noticed a smudge on my freshly cleaned storm door.  She must have put her hand to the glass to peer in to see if I was inside since I didn't answer the door right away.  What is the probability that a pizza delivery person will go the wrong house and smudge a rarely cleaned, but freshly cleaned window?  (As ds would say, in this case it was a 100%!)


  1. That is interesting. Maybe the vortex switched and everybody that comes in the neighborhood undergoes a phase shift...just kidding. That is odd.

  2. It is amazing today how many people do not know that odd numbers and even are on opposite sides. I am so used to that looking for locations I take it for granted. But for a LEO or delivery person to go to the wrong side is 'ignorance'.

    "Bathroom at the wrong time, I mentioned that in a blog entry coming up later today. LOL."