# Can anyone figure this math problem?

By cfitzarl ยท 7 replies
Mar 12, 2007

1. I saw this in one of the ads here, and I was wondering if there was anyone who was able to figure this out if possible :grinthumb: !

2. ### NodsuTS RookiePosts: 5,837   +6

Ehm. Without bothering to look into it..

It's just an expression. What is the problem? Find x? Find sigma? See if it's solvable? Find different values of X whete sigma->infinity? Do a Fourier transform on the thing?

3. ### Po`GirlTS RookiePosts: 595

As I had a few hours on my hands,I decided to learn mathematics -

It`s the expression for the computation of the standard deviation in a data set.

"The standard deviation is simply the square root of the variance.You calculate it by first calculating the mean.
Then you go through each datum in your set and subtract the mean (this makes the set centered around the mean) and square it.
You add all these numbers together and divide by number of values in your set,subtracting one from that number before dividing.
This is the variance. Take the square root of that and you have the standard deviation.

The standard deviation tells us how spread out the data are from the mean,
and is useful in error predicton and correction.

More pain HERE and HERE

5. ### jobeardTS AmbassadorPosts: 10,831   +894

hum; last time I had to plot Stdv, the equation was as shown in the attachment

6. ### cfitzarlTechSpot ChancellorTopic StarterPosts: 1,975   +9

I didn't really think about the solvent :grinthumb: ! I'll be in Algebra II Next year... (easy for me).

7. ### robbo13TS Rookie

fourier series /transform

the equation relates to fouier series which is used to calulate various forms of oscillations in modern tecchology. calulating harmonics and the fundamental rf signals, using analog signals to create a digital signal.
So a periodic signal can be represented as trigonmetrical series in sine and cosine terms.

8. ### mikescorpio81TS RookiePosts: 293

Err ... what he said!