I guess my little elevator just doesn't go all the way up cause I fail to understand what all the ruckuss is over the concept of standard deviation. For me, if I wanna know something like standard deviation or other unusual math related issues, I find a simple web search can turn up a good deal of information for example, a search for "standard deviation" in Yahoo gave me the following:
Here is one formula for computing the standard deviation. A warning, this is for math geeks only! Writers and others seeking only a basic understanding of stats don't need to read any more in this chapter. Remember, a decent calculator and stats program will calculate this for you...
Terms you'll need to know
x = one value in your set of data
avg (x) = the mean (average) of all values x in your set of data
n = the number of values x in your set of data
For each value x, subtract the overall avg (x) from x, then multiply that result by itself (otherwise known as determining the square of that value). Sum up all those squared values. Then divide that result by (n-1). Got it? Then, there's one more step... find the square root of that last number. That's the standard deviation of your set of data.
Now, remember how I told you this was one way of computing this? Sometimes, you divide by (n) instead of (n-1). It's too complex to explain here. So don't try to go figuring out a standard deviation if you just learned about it on this page. Just be satisified that you've now got a grasp on the basic concept.
The more practical way to compute it...
In Microsoft Excel, type the following code into the cell where you want the Standard Deviation result, using the "unbiased," or "n-1" method:
- =STDEV(A1:Z99) (substitute the cell name of the first value in your dataset for A1, and the cell name of the last value for Z99.)
Or, use...
- =STDEVP(A1:Z99) if you want to use the "biased" or "n" method.
(acknowledgements to http://nilesonline.com/stats/stdev.shtml for this tidbit)
Maybe I am just to simple to understand what the situation here is...but I do understand the concept of keeping it simple.
Sir Metro
A man who is good does the right thing when others are watching...a good man does the right thing even when no one is watching.