GR8677 #40



Alternate Solutions 
There are no Alternate Solutions for this problem. Be the first to post one! 

Comments 
walczyk 20110406 22:36:51  how is the number of counts also the average? It seems like magic to me..oh wait i see it. you just say "counts per hour" and then it becomes an average. Its tricky because it doesn't tell you what time scale the average should be in. Weird problem.   spacemanERAU 20091015 12:14:24  Im not smart so I was wondering if there was a way for nonintelligent people to solve this problem? I would have had the normal SD equation memorized and been lost as to how to use it to solve this problem. Any help is greatly appreciated.
ramparts 20091030 15:28:46 
Counting problems use the Poisson distribution, and the error scales as . Just something you've gotta memorize :) Maybe from your freshman physics lab, as it was for me.

mpdude8 20120415 21:41:44 
I, personally, like to see problems where I get almost no information in the question. You know, then, that the answer has to be something simple, or something purely based on logic and reasoning.
The only "number" you're given is 9934. Even if you forget the relationship given in the original solution above, you might try the square root as a guess. This yields a result suspiciously close to 100.
Not even a physical or mathematical argument  but with only 90 seconds allotted per question, sometimes you have to try a clever guess.

justin_l 20121108 11:05:14 
Basically, whenever you see standard deviation in statistics/counting, you should see Square Root of N. Standard deviation is ALWAYS related to the square root of n in counting problems, and it's always associated with square roots in general.
Any time you see standard deviation, think square root.
Specifically if it's a counting problem.

  erc 20051105 08:01:34  Typo alert: 9934 ~ 10000  too many zeros in solution.
yosun 20051105 23:12:47 
Thanks erc for the correction!

 

Post A Comment! 

Bare Basic LaTeX Rosetta Stone

LaTeX syntax supported through dollar sign wrappers $, ex., $\alpha^2_0$ produces .

type this... 
to get... 
$\int_0^\infty$ 

$\partial$ 

$\Rightarrow$ 

$\ddot{x},\dot{x}$ 

$\sqrt{z}$ 

$\langle my \rangle$ 

$\left( abacadabra \right)_{me}$ 

$\vec{E}$ 

$\frac{a}{b}$ 





The Sidebar Chatbox...
Scroll to see it, or resize your browser to ignore it... 

