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Questions tagged [standard-deviation]

Standard deviation (represented by the symbol sigma, σ) shows how much variation or "dispersion" exists from the average (mean, or expected value).

The standard deviation of a random variable, statistical population, data set, or probability distribution is the square root of its . A standard deviation close to 0 indicates that the data points tend to be very close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the data points are spread out over a wider range of values.

The standard deviation of X is the quantity

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Mean and Standard Deviations of coefficient vectors using R?

How can I calculate the mean and standard deviation of each of the coefficients over the N=1000 MLR model fits using R? Here's my function: simfun <- function(a=56.25102409,b=1.78977412,c=0.08664925,n=18,x1.sd=18.87671,x2.sd=18.87671,e.sd=18.87671)…
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In R, a rolling Standard Deviation that can skip over NA values?

I am wondering if there are any fast R functions that can compute a rolling Standard Deviation on a vector, while skipping over any NA values in the middle of said vector, so the vector still lines up with the original data? The package TTR has…
Contango
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Getting data from an ArrayList to then use in calculations?

So I have an assignment, and it requires me to calculate the average of each students marks for each assignment then to calculate the average of each assignment. I am able to calculate the average for each student but i'm having trouble with the…
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R barplot with standard deviation

I am a new R user and am having trouble graphing some data in a bar plot. Sorry in advance if this is really easy to do, and I just can’t figure it out. I have six sets of data: 3 data sets for car #1 at 1, 5, and 10yrs, and 3 data sets of car#2 at…
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r conditional standard deviation on 2 matrices

I am trying to calculate the conditional standard deviation of a matrix B (for every column) based on the values of matrix A. #conditional function foo<-function(x,y) { out<-sd(y[abs(x)==1]) return(out) } #create the…
user2493820
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Mean, SD, ANOVA for repeated measures longitudinal

Three Measurements (Time) are nested in Networkpartners (NP) which are nested in Persons (ID). The variable NP.T (created according to the answer mentioned here) indicates the number of Networkpartners (with no missing value on the Outcome) a…
user2647568
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iterating over lists finding standard deviation of each point

I have this section of code that is supposed to find the standard deviation of each number in A, where A is a list of lists consisting of 7 values. def sigma(A): diff = 0 positives = [b for b in A if b >= 0] if positives: mean =…
KJo
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finding standard deviation down a column of data in python

A.append([(float(a) + float(b) + float(c))/3, (float(d) + float(e) + float(f))/3, (float(g) + float(h) + float(i))/3, (float(j) + float(k) + float(l))/3, (float(m) + float(n) + float(o))/3, (float(p)…
KJo
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How to calculate the standard deviation for every 100 points in a nx3 vector?

Suppose I have a matrix with n rows, each containing three coordinates, (x, y and z). I want to calculate the standard deviation for every 100 set of points in MATLAB. For example, for the first 100 x coordinates I apply std, then same for the y and…
Eliza K
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Calculate online standard deviation

I want to calculate the Standard Deviation for every value which comes to the system in run time. I'm not sure how to implement it. I implemented the online average def online_avg(last_avg, last_N, new_val): return…
Bush
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changing the values of a list if they are more than a certain value

I am reading in a list from a text file and taking the standard deviation of this list, I want to know how to make values outside one standard deviation away from the mean to just be used as one standard deviation away from the mean. Here is the…
astrochris
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How to calculate and display standard deviation?

I am trying to display a spectrum and it's upper and lower deviation. Therefor I have a Class, "SpectrumClass" where the cooridantes are stored in a DataTable (dtCoords). The spectrum I am showing is an average of several other spectra. Whith those…
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Weighted Standard Deviation

Hi I want to calculate weighted standard deviation in SQL Server 2012. Is there any inbuilt function as of standard deviation in SQL Server or how to built a user define function in SQL Server.
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standard deviation arraylist error

I am getting an error when I try to retrieve the individual values to find the variance in the process of calculating the standard deviation. I can't figure out whether to use .get() or .getValue and I am lost. I have already calculated the average.…
user2007843
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calculating standard deviation results index exceeds matrix dimention error

i am calculating standard deviation of 250x250 image but i am getting following error can anyone help please.. 210.2683 ??? Index exceeds matrix dimensions. Error in ==> test at 5 std1=std(g(:)); my code snippet is kl=imread('ai427.jpg'); …
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