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jjohn (22)

jjohn
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http://taskboy.com/
AOL IM: taskboy3000 (Add Buddy, Send Message)

Perl hack/Linux buff/OSS junkie.

Journal of jjohn (22)

Sunday August 10, 2003
11:04 AM

Values, both expected and unexpected

[ #14033 ]

It was a wise being of indeterminant origin who said "I love to get something I already own for Christmas because I know I will like it." Initially I discounted this remark as being another one of his sugar-induced verbal ticks, but today I learned how Solomon-like his wisdom truly is.

I'm lucky enough to live in a apartment that also has a basement storage area. While this is little more than a walk-in closet for suburbanites, it's a veritable warehouse by Boston standards. The compartment measures roughly 7' deep, 3' 1/2" width and 6' high (using space-age math I find that I have 147 cubic feet of storage [good to know when I have to store cubes]). Since I've lived at the same address for over eight years now, the contents of the boxes contained in that closet are more than a little mystery to me now.

While waiting for my laundry, I started pulling out the boxes and examining the contents. Wow! I have a lot of cool stuff! Here's an unordered list of what I found

  • Two Weber grills (useless to me, so I chucked them)
  • A disproportionate amount of holiday paraphenalia for a single male
  • The Adventures of Tom Bombidill
  • Two 2400 baud modems
  • A crappy pair of 1/8" phono-jack headphones
  • 1 Apple Quadra
  • 1 PowerMac 7100/40
  • 1 WinBook 486/33 laptop
  • 1 Brother daisy wheel word processor (from the late 80's)
  • My old notebook from the one music theory class I took at BC
  • Gygax and Arneson's Dungeons & Dragons, vol 1: Men and Magic
  • Many of my D&D Expert, Companion and Master rulebooks, modules and the rare Gazetteers (which I really enjoy reading now).

I'm like eBay, but without teh suck.

In other jjohn news, I converted about 10-15 lbs. of coins into cash money at the super market that has a machine charging 13% of the gross to count the change. As far as I'm concerned, recovering my change is found money, so I happily use this service. Others surely will find this charge usurious. Whatever your prefence, the dread machine displays the tally of the coins it has identified. Because the laundry machines take quarters only, I try to harvest all the quarters I can before turning in my small bucket of metal (like a nineteenth century prospector).

And that's where this journal turns into a word problem.

For the sake of argument, say pennies, nickels and dimes are equally likely to be in my collection of change (who's to say they are not?). What's the expected value of the average coin? Given that I had roughly 2000 coins, how much money (minus the conversion fee) would you predict that I walked away with?

I'll post the answer later.

UPDATE: The expected value of J. Random coin is about 5.3 (16/3). There were about 2000 coins, so one would expect the value of the booty was to be about 10000 cents or 100 dollars. $13 worth of fees (after reading the posts, I'm thinking it was closer to a %9 fee) less means that I should walk away with $87.

In reality, I walked with $88 and had closer to 1800 coins.

Math is fun when it's fuzzy!

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  • I walked away with like $80 from a single jar of coins, though the machine's service charge was less than 10% IIRC.
  • Others surely will find this charge usurious.

    Yikes! I thought 8% (which is what I think the machines at Safeway here charge) was outrageous.

    who's to say they are not?

    I am. I find it unlikely that either nickels or dimes are anywhere near as common as pennies in your change. You might find some messages in this thread from June on rec.puzzles [google.com] interesting.

    --Your YAPC 19100 roomie

    • I find it unlikely that either nickels or dimes are anywhere near as common as pennies in your change. You might find some messages in this thread from June on rec.puzzles interesting.

      Reality is far too complicated for me. I like my simple models better (and those folks on the thread you pointed to have a sickening amount of free time and brain cycles ;-).

  • I was closest without going over!