MATLAB: Syntax help with script

scriptsyntax

I am wanting to put this equation into matlab, but I am having problems.

I am wanting to find the standard deviation without the built in matlab function. I have a mean_temp and a mean_pres already set up and displaying properly. Can I get some help how to incorporate those values (i have i=1:30) for each temp and pressure.

The standard deviation equation is:

(sum i=1 to n (xi^2-nxbar^2))/(n-1)

My xi should be my values each 1 through 30. xbar is my mean.

Thank you in advance.

Best Answer

assuming x is an nx1 column vector...

sum(x.^2-mean(x)^2)/size(x,1)

also I think your equation is wrong: http://en.wikipedia.org/wiki/Standard_deviation you'll want to square after subtracting, not before.

sum((x-mean(x)).^2)/size(x,1)

Related Solutions

MATLAB: A single line of MATLAB code that computes the mean and standard deviation of a 1‐dimensional array named A of numbers??

m=sum(x)/numel(x);  
s=sqrt(sum((x-m).^2)/(numel(x)-1));

Best wishes

Torsten.

MATLAB: Taking An Average of Multiple Outputs From For Loop

Hi Celeste,

You can take the mean of every reuterned M value, if you store the calculate M value in an array. The code overwrites the M value for each iteration it. So, update the code as below:

for it = 1:10
A=randn(10);
% Calculate Sum
S=sum(A,'all');
% Divide by the Number N in the Matrix to Find the Mean
M(it)=(S/(length(A)));
display(M(it));
% Find variance
sum1=0;
for i=1: length(A)
    sum1=sum1+ (A(i)-M(it))^2;
end
V(it)=sum1/length(A);
display(V(it));
SD(it)=sqrt(V(it));
display(SD(it));
end
% M, V, and SD contains the output of each iteration. Then, apply mean as below
meanM = mean(M);
meanSD = mean(SD);

Hope this helps.

Regards,

Sriram

Best Answer

Related Solutions

MATLAB: A single line of MATLAB code that computes the mean and standard deviation of a 1‐dimensional array named A of numbers??

MATLAB: Taking An Average of Multiple Outputs From For Loop

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