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What's Going On?

from giga to nano: large and small numbers

Gordon Speer's Metric Prefixes

There are many more molecules in a glass of water than there are glasses of water in the sea.
--Lewis Wolpert

Moore's Law

exponential change: network effects

There are many more molecules in a glass of water than there are glasses of water in the sea.
--Lewis Wolpert

some extreme numbers

6 billion people on Earth

6 billion birds in U.S.

10^21 stars in universe

10^18 insects on Earth

one in every four animal species on Earth is a beetle.

10^23 protozoa living in digestive tracts of insects

'Social insects' could make up an incredible 20% of Earth's total animal biomass.

Microbes And Me
by Jennifer LeBlanc
Explorit Science Center, January 2002

Adults have between 11,000 (forearm) and 1.5 million (scalp) bacteria per square centimeter of skin. ... Every day, we produce 10 billion skin flakes, called squames. In a year, these dead, discarded skin flakes weigh in at over two kilograms.

What about a terabyte?

When I had a hundred-megabyte (MB) hard drive, it sounded a little far out to think having all my music on a portable personal computer. What about ten years from now when I put all my personal information into a device? How about a terabyte (TB) -- 1000 gigabytes?

If it seems hard to imagine what to do with that space, I try to remember what I would have thought of a 20-GB drive in 1989.

Everything I will read in my lifetime stored as text is unlikely to amount to more than a few GB.
I could snap 100,000 JPEGs and still use only 10 GB.
Several hundred music CD’s turns into about 20 GB using MP3 compression.

Then I can really start eating up space. A hundred DVD movies plus 250 hours of TV and I will still have used only a little more than a third of my one-terabyte hard drive.

Of course, I'll fill it up and want another. What if I wore a microphone every minute of every day and recorded my whole life? At compressed voice-grade (8 kilobits per second), I might need a terabyte if I live into my 80's.

Conclusion: most of what I would want to store is audio and video, and everything else is incidental.

Then the problem will be to find it. Indexing and retrieval will be the big challenges.

Superfluous Accuracy

On the Medaille MBA spreadsheet with all the student records, each student has a row. For row 15, (your last names begin with C), column DI has this forumula:

=IF(COUNT(AM15:DH15)=0,0,(AN15+AP15+AR15+
AT15+AV15+AX15+AZ15+BB15+BD15+BF15+BH15+
BJ15+BL15+BN15+BP15+BR15+BT15+BV15+BX15+
BZ15+CB15+CD15+CF15+CH15+CJ15+CL15+CN15+
CP15+CR15+CT15+CV15+CX15+CZ15+DB15+DD15+
DF15+DH15)/COUNT(AM15:DH15))

Looks pretty scientific, doesn't it? For rows 15, 16, and 17, (your last names begin with C), it produces the following grade point averages.

3.671428571
3.714285714
3.842857143

Student 15's grade point average is 3.671428571. Therefore, he didn't get as good grades as Student 16, whose grade point average is 3.714285714. I guess he isn't as smart. Or maybe he aren't as good a student. I think student 16 with the higher average should get an A but student 15 with the lower average should get an A-. After all, we can't reward mediocrity!!

Any statistician would say, Give me a break. That kind of accuracy says more about the measurer than about the thing measured, that is, it says more about the teacher than the student.

It is sometimes called "superfluous accuracy", like saying that the Great Pyramid is lined up North/South to within a ten-thousandth of a degree. There isn't any stone on that pyramid that anyone can measure whether it's lined up in any direction to within .0001 degree. How far have plate tectonics shifted Africa between the time the pyramid was built and the time its North/South orientation was measured? More than .0001 degree, to be sure.

In your case, if you took all those test again, right now, how would you score? More importantly, what does your average predict about how well you will do your job?

Where does all that accuracy come from? It comes from throwing away estimates of error. You take a test and the teacher scores it as an 88% and he throws away the plus and minus. He averages three tests, all of which had a plus or minus thrown away because otherwise it would multiply, creating a course grade with a wide estimate of error. Finally, all these imprecise course grades are averaged, given equal weight, to create a grade-point average to the tenth decimal place.