Sigma Definition and 217 Threads

Hi all, I'm reading some journal articles and in many of them, when they quote a result, they add 'at the 2 to 3 sigma limit.' I realize this is some sort of statistical quantity, but what exactly does it mean, and do lower values of sigma mean better results? Thanks

Hi there, We are about to use that sigma sign in chemistry we have however not got told about it in math. SO therefore I am asking you if you could give me a brief introduction to it and how to use it and etc.

Help! We need to solve the following problem: ∞ r-1 find x if ∑ (3x/2) = 4 r=1 We know the answer is 1/2, but we have no idea how they got that answer. Can anyone help? Thanks, Sammie

Trying to help my son & I am in Waaaaay over my head. He has a string of numbers and needs to come up with the correct Sigma Notation equation. 3, 6, 12, 24, 48, 96

Let \Sigma = { \beta,x,y,z} where \beta denotes a blank, so x\beta \neq x, \beta \beta \neq \beta, and x\betay \neq xy but x \lambday = xy. Compute each of the following: 1: \parallel \lambda \parallel 2: \parallel \lambda \lambda \parallel 3: \parallel \beta \parallel 4...

can anyone point me in the right direction to somewhere i can find out about sigma polarisation. i want to know how it is defined. thanks

Okay, I think this problem relates with sigma notation (I'm not good at it) the sequence given is 2, 4, 8, 16, 32 ... It wants you to find the sum from 1-50 So the equation thing is 2^N? How do you find all the sums again...? Thanks

Hey all, I've been working on learning to solve some PDE's. To do this I've been reading other people's tutorials. Here's one on the heat equation: http://www-solar.mcs.st-and.ac.uk/~alan/MT2003/PDE/node21.html This is pretty much the same as the others I've read on the heat equation...

I'm now studying Lebesgues measure on R^n, and when we finished constructing L (all measurable sets), we moved on to Borel sets and so on. My question is, is there is no way of extending the Lebesgues measure on a larger family than L? Can it be done while still saving the nice properties of...

Could somebody please explain the 2-fold degenerate sigma 2p is lower in energy than that of 4-fold degenerate the pi 2p bondings state in the O2 molecule? Does it have anything to do with resonance energies perhaps?

Show that: \sum_{k=0}^{N} a_k = \sum_{k=M}^{M+N} a_{k-M} I did this, my answer is: \sum_{k=0}^{N} a_k = a_0 + a_1 + a_2 + ... + a_N \sum_{k=M}^{M+N} a_{k-M} = a_{M-M} + a_{M+1-M} + a_{M+2-M} + ... + a_{M+N-M} = a_0 + a_1 + a_2 + ... + a_N Now, I have to use this to prove that: \sum_{k=M}^{N}...

Please any help. Use the symbols \beta and \sigma definition of limit to prove that limit (x,y)\Longrightarrow(0,0)x+y/x\x^2+y\y^2=0

Series and "Sigma" Notation I have been revising over the sigma/sequences and series chapters, this is the second question now where i have had different answers to the book - yet- my answers seem to work - i think... The question : Write in \sum notation 1 - 2 + 4 - 8 + 16 - 32...

wondering how "sigma" is used I think this is the right forum. I wondering how "sigma" is used, the definition is summation but what does that mean, is it just the sum? Can some 1 give me an example of how it works. Thnx.

7 ---- \ / 1 <- *note: the 1 should be more to the right. ---- N=3 Ok, this might be dumb :blushing: , but it think the answer for this is 1 but I'm just making sure. cuz i know that for example if it is 7 ---- \ /...

I would like to know what sigma is and what it does. What is sigma? What does it stand for? How does it work? Do you have any examples of how it works? any help would be appreciated (im not sure if this should be in the calc section or not)

An infinite nonconducting sheet of charge, oriented perpendicular to the x-axis, passes through x = 0. It has area density s1 = -3 µC/m2. A thick, infinite conducting slab, also oriented perpendicular to the x-axis, occupies the region between x = a and x = b, where a = 3 cm and b = 4 cm. The...