deviation Definition and 402 Threads

Can someone please explain how the standard deviation is relevant when we are talking Brownian motion? And why is statistics important when we want to understand the movement of a brownian particle?

Converting Binomal cpk to a "fair dice" deviation. Hi, I would like to detect low probability in a "fair dice" problem being used for graphing of outliers. The actual data is binned into cells of 1% probability which form a histogram of the dice faces can be drawn. (The original data...

Homework Statement There are 10 observations. (a) Suppose the IQR is 8. Is it possible that the standard deviation is 1? (b) Suppose the standard deviation is 8. Is it possible that the IQR is 1? Homework Equations IQR = R3 - R1 The Attempt at a Solution My argument is that (a)...

...I understand why it becomes more and more insignificant as the value of n increases, but what is the purpose of subtracting 1 from n in the sample population in the first place? Also, what is the purpose of squaring the result of x values minus the mean? I can do the problems. I'm just...

I've calculated the mean difference of my (normally distributed) data set. The mean difference is defined as: Now, I'm trying to calculate the "mean difference deviation" in order to generate a confidence interval for this quantity ( "95% of the differences in the set are greater than...

One explanation of the deviation of o-ray and e-ray is done using Huygen's wave fronts which for the o-ray is a circle and for the e-ray is and ellipse. The ellipse is given by the two refraction induces of 1.658 and 1.486 (http://physics.info/refraction/) are "a" (major axis) and "b" (minor...

Homework Statement Let x_{1},...,x_{n} be n observations. If y_{1},...,y_{n} is another set of observations s.t. y_{i}=ax_{i}+b , prove that s_{y}=|a|s_{x} . The Attempt at a Solution Attempt at a proof: Since \bar{y}=a\bar{x} +b then \bar{x}=(\bar{y}-b)/a and...

Hello, I'm doing some nonlinear regression fitting, and I have a set of data with n data points and I am fitting the data to a model which contains 3 parameters. I can get a confidence interval from the program I'm using for each parameter, but how can I calculate the standard deviation for...

Hello all This is not homework, i work in engineering. I have some data in a table, there are 3 columns and 5 rows. The data relates to how high or low one rail is to the other. The data was collected across 3 days. At each 7m intervals the height of the right hand rail was...

Can anyone help me to find out the definition of "carrier swing"&"deviation ratio"? The definitions which i found on surfing the net is too vague.Can someone help me with this?

The length of time, t minutes, taken to do the crossword in a certain newspaper was observed on 12 occasions. The results are summarised below. Σ(t − 35) = −15 Σ(t − 35)^2 = 82.23 Calculate the mean and standard deviation of these times taken to do the crossword. My real problem is finding out...

This isn't even a homework question but in my textbook there is an example on how to find the angle of deviation in a prism. I understand how they got all the angles listed in the picture but what I cannot understand is how the angle of deviation can be found from 70 - 12 = 58 degrees (answer in...

I missed the lesson on this and i can't figure out how to do this question with the data given. Homework Statement A class of 20 students takes a test. The score, x , for each student was recorded by the teacher. The results of summarised by: ∑(x-10) = 208 and ∑(x-10)² = 2716 i) calculate...

Homework Statement The apex angle of a prism is 50.0^\circ and the index of refraction of the prism material is 1.66. What is the minimum deviation angle? Homework Equations Snell's Law: n_1\sin(\theta_1)=n_2\sin(\theta_2)The Attempt at a Solution How would you approach this? I get a...

Homework Statement i'm given the population mean and standard deviation. A new batch comes in and given a random sample. the question asks do i believe the new batch has a different mean from the overall average? Homework Equations The Attempt at a Solution so i got the mean and...

Hi, Can anyone point me to a reference for the statistical properties of the sample standard deviation of a sequence of identically distributed normal random variables subject to some form of serial correlation? Thanks, rhz

Hello All, I am trying to figure out how to find the standard deviation or error in sets of data. So let's say I have sets x1, x2, x3 and x4 with various values and I found the average and standard deviations for it. Now I have to take the averages, let's say a1, a2, a3, a4, and normalize...

Hi Say I have a linear problem Mp = d, where d is our data, p our parameters and M our "observation matrix" (see http://en.wikipedia.org/wiki/Inverse_problem#Linear_inverse_problems). So what we are dealing with is an overdetermined problem. Now, I have read an example where we have a...

Hello,world [PLAIN]http://img718.imageshack.us/img718/1433/unledkzg.jpg Could you explain the reason for this?This would help me so much Thanks in advance

We all know that carbon shows the configuration 1s2- 2s2- 2p2 But, since half-filled and fully filled orbitals are more stable, why doesn't it show the configuration 1s2- 2s1- 2p3 ? Why doesn't the 2s orbital give 1 electron to 2p, as in the case of Chromium, where one electron goes from 3d to...

Not sure if this is where this question belongs because the course I am doing is predominately calculus based (Applied Physics, University level) but we have a small statistics component for obvious reasons. Any who, sorry if it's in the wrong spot. Homework Statement Intravenous fluid bags...

Hi If I have measured the resonance frequency of three sets of resonators and calculated the mean, variance and standard deviation for each set. How do I add the three variances and standard deviations to get an overall variance and standard deviation? Well, I know that the standard...

I am working with some wind speed data and need to work out the standard deviation of the magnitude of the horizontal wind. Unfortunately the only information I have is the standard deviation for the streamwise and cross-stream components of the wind (which are orthogonal). Is it possible to...

For the following data set of eight values, give the MEAN, DEVIATION (DEV), and AVERAGE DEVIATION (AD). Show a sample calculation for each: 0.77, 0.92, 1.12, 1.00, 0.96, 0.88, 1.16, 1.02 Homework Equations Well before we began, can anyone take the courtesy and see if I'm getting the...

Homework Statement A ray of light passes from air into benzene. For its deviation angle δ = |θ1 - θ2| to be 9.5°, what must be its angle of incidence? The refractive index of benzene is 1.501. Homework Equations Snell's law The Attempt at a Solution From Snell's law we have sin...

Homework Statement Suppose that the systolic blood pressure of 20 year old females is normally distributed with mean 120 and standard deviation 15. a.) What proportion of 20 year old females will have readings between 115 and 125? b.) If you selected a sample of 64 people from this...

Homework Statement Write a C++ program that accepts 10 floating-point values from a user and determines and displays the average and the standard deviation. All values more than four standard deviations away from the average should be dropped and then the new average and standard deviation...

Consider the Uniform distribution (continuous) U(-1,1) which has p.d.f. f(x) = 1/2 for -1 < x < 1 and 0 otherwise. I have calculated the Fourier transform using the characteristic function and got fhat(epsilon)= sin(epsilon)/epsilon How do I calculate the standard deviation of this...

Homework Statement The average monthly expense of a certain family during 11 months is 4000 shekels, with a standard deviation of 100 shekels. Afterwards they added to the calculations the family's expense at the 12th month, and they found the average remained unchanged. A) What was...

Homework Statement The grades distribution in class is 10, 8, 8, 7, 7, 7, 6, 6, 4 What's the standard deviation? The Attempt at a Solution I found the average is 7 (which is true) and used the formula for standard deviation. I checked it twice on the calculator but I'm still...

Let's say I have a big, 50-sided die, with values ranging from 1-50. I want to find the exact standard deviation of the dice roll by hand. I would like to avoid subtracting the mean from each possible value, if at all possible. How do I do that?

Homework Statement Use the formula: n=(sin(A+D)/2)/(sin(A)/2) to find D for an equilateral prism of index of refraction n=1.50 (where A=apex angle for a prism=60 degrees in this case, and D=minimum angle of deviation) Homework Equations Snell's Law: (n1)sin(i)=(n2)sin(r)...

Suppose the men in a country have a mean life span of 79 with a standard deviation of 8. And the women in the country have a mean life span of 83 and also a standard deviation of 8. Furthermore, suppose the life spans are normally distributed. What is the mean life span of the entire...

How to convert error to standard deviation? I explain my simple question: I have a program that requests the standard deviation of a physical measurement. But I only have the error, let's say v=-3.445643 +- 1.5%. How do I make the conversion? Please

Given a set of random real numbers G=(a, b, c, d, e, f, ...), I am supposed to calculate the number T such that the sum of squared errors between that number and all the elements in G is mimimum. Intuitively, this should be the average of the numbers in G, but I am not sure how to proceed with...

How much slower is time ticking inside the Sun, compared to the surface, and how can it be calculated?

Hi, I have some problems with interpretation of my dates of magnetic susceptibility measured on heavy compound Ce2RhIn8 doped by Pd on Rh site. The curves measured along c-direction follow the Curie-Weiss law only in the high temperature region (~200-300 K) and then deviate from it. The curves...

Homework Statement This is a two part problem: 11) The index of refraction for violet light in silica flint glass is 1.66, and that for red light is 1.62. What is the angle of deviation for the red ray passing through a prism of apex angle 59.6◦ if the angle of incidence is 54.8◦...

I understand MAD, but I cannot figure out this question. Here's the information. Daily high temperatures in St. Louis for the last week were as follows: 92, 91, 94, 95, 96, 88,90. The mean absolute deviation based on a 2-day moving average = 3.20 How in the world is it 3.20? I've tried...

Homework Statement A high jumper knows from experience that she can clear a height of at least 1.78m once in 5 attempts. She also knows that she can clear a height of at least 1.65m on 7 out of 10 attempts. Find to 3 dp the mean and standard deviation of the heights the jumper can reach...

Homework Statement Carbon rods with a nominal diamter of 1.5cm, it is only acceptable within the limits of 1.495 to 1.505cm. the actual diamter normaly distributed with a mean of 1.501cm with standard deviation of 0.003cm. what will be the percentage of the rods which are rejected if 1-...

Homework Statement i have a few results of measurements, with different measurement uncertainty: L=5\pm0,2, L=5,1\pm0,1,L=5,2\pm0,3,L=5,3\pm0,1,L=5,4\pm0,2 and how can i count standard deviation and final result of measurement with uncertainty? The Attempt at a Solution i counted arithmetic...

Hi, In Holstein-Primakoff process, nl = al*al and Nl Psinl = nl Psinl Why (1-Nl/2S)1/2 Psinl = (1-nl/2S)1/2 Psinl ? Since the operator (1-Nl/2S)1/2 is not linear, I think it should not work as a linear operator. Please let me know if I misunderstood something.

Hello all, I am trying to figure out the following question with no luck: I have a box of resistors, mean 100 ohms and SD of 20 ohms. I form a subgroup of these resistors with mean of 100 ohms and SD of 5 ohms. Find the standard deviation of the remaining sample. The question does not...

Question on test---standard deviation Was hoping someone could help me out with a question. It was on a online test and the answer i got i wasnt sure if it was the right answer. The question was as follows: The no-show rate for passengers with reservations on a flight run by wizair is...

Let X and Y be the per dollar return of 2 stocks. Suppose that both have an expected return of 0.05, both have a variance of 0.0009 and covariance(X,Y)= -0.001. Suppose that you invest $50 in the stock with return X and $100 in the stock having return Y 1) Calculate the expected return of...

Can somebody explain to me why we have to square the variances when calculating the deviation and then finding the square root(whc is suppose to reverse the squaring) ,it doesn't make sense to me

I have a question of testing of hypothesis about mean, the population S/d is not given rather it says "a client gave Quality Associates a sample of 800 observations taken during a time in which that client’s process was operating satisfactorily. The sample standard deviation for these data was...

Hi all, I've done a regression and have the Standard Error of the X co-efficient (i.e. the slope). How do I change this figure to the standard deviation? Is the formula STD DEV = (STD ERROR)/(degrees of freedom)^0.5 Where degrees of freedom = N - number of X coefficients. ...

#of nickels needed when only standard deviation is mentioned A previous study of nickels showed that the the standard deviation of the weight of nickels is 150 milligrams. A coin counter manufacturer wishes to find the 98% confidence interval for the average weight of a nickel. How many...