View Full Version : Statistics Riddle


Cpt. Cynical
Sep 29, 2006, 08:42 PM
My stats instructor gave the class an interesting statistical riddle today. Here's how it goes:

Calculate:

111,111,111 X 111,111,111

How is the answer like the normal curve (standard normal distribution)?

The answer, I think, is 12,345,678,987,654,321. How is that like the normal curve?

Well, I can figure out that the number obviously looks "bell-shaped" in that it starts with 1 on the outside and ascends to 9 in the middle.

Can you folks think of anything else? This is getting on my nerves, as if I am missing something obvious because I'm not savvy with statistics. :confused:

brennan
Sep 29, 2006, 08:47 PM
123...321 would just be a triangle

1x1=1
11x11=121
111x111=12321
1111x1111=1234321

Pattern established. Not a bell curve though.:confused:

Perfection
Sep 30, 2006, 02:38 AM
Brennan seems to be on the mark here.

I'm curious as to the origin of this riddle.

Brighteye
Sep 30, 2006, 02:48 AM
You could also say that as you multiply larger 1111 numbers a bar graph of the result approximates ever more closely to a triangle, just like larger ns give a mean that approximates more closely to the normal distribution.
Yes, I know its tenuous.

Perfection
Sep 30, 2006, 02:53 AM
I wonder how the digit pattern changes under different bases. Someone mak me some graphs! I'd do it now, but it's 3:00 AM.

brennan
Sep 30, 2006, 07:20 AM
Binary:

1x1 = 1
11x11 = 1001
111x111 =110001
1111x1111 = 11100001
11111x11111 = (on my calculator it's E for error, but..) 1111000001
111111x111111 = 1111110000001

Odd pattern. Interesting though.

Elrohir
Sep 30, 2006, 07:22 AM
Binary:

1x1 = 1
11x11 = 101
111x111 =110001
1111x1111 = 11100001
11111x11111 = (on my calcukator it's E for error, but..) 11110000001

Odd pattern. Interesting though.
I think it's capital "E" for exponent.

brennan
Sep 30, 2006, 07:33 AM
Trust me man. I know what notation my scientific calculator uses for exponent. When all it does is say -E- it means the number is too big to show. (it doesn't show exponents in bases other than 10).

Xenocrates
Sep 30, 2006, 08:11 AM
Is it possible, stat fans, that the OP's answer 12,345,678,987,654,321 should be interpreted 10^1, 10^2 etc?

I know that also wouldn't resemble a normal distribution as the top should flatten off, but at least it's curved......

Now this is driving me crazy too (a short drive Brennan ;) ), how much like a normal curve should this be exactly?

nihilistic
Sep 30, 2006, 08:19 AM
My stats instructor gave the class an interesting statistical riddle today. Here's how it goes:

Calculate:

111,111,111 X 111,111,111

How is the answer like the normal curve (standard normal distribution)?

The answer, I think, is 12,345,678,987,654,321. How is that like the normal curve?

Besies symmetry, it is not. That's the end.

Well, I can figure out that the number obviously looks "bell-shaped" in that it starts with 1 on the outside and ascends to 9 in the middle.

Can you folks think of anything else? This is getting on my nerves, as if I am missing something obvious because I'm not savvy with statistics. :confused:

There is nothing obvious besides the stupidity of the question. Likewise this question also has nothing to do with statistics and everything to do with numerology.

Red Stranger
Sep 30, 2006, 01:46 PM
It's like statistics because in the end it's just numbers. Anyone can try to make sense of the numbers or try to find patterns in the numbers. But it's just an illusion.

Perfection
Sep 30, 2006, 02:00 PM
It's like statistics because in the end it's just numbers. Anyone can try to make sense of the numbers or try to find patterns in the numbers. But it's just an illusion.
Well, statistical ideas are very important in physics, and physics tends not to be an illusion. ;)

Nice joke, though.