gaussian probability function matlab

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Kelly Howard 2016-1-25

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https://ww2.mathworks.cn/matlabcentral/answers/265132-gaussian-probability-function-matlab

编辑： Kelly Howard 2016-1-28

采纳的回答： Star Strider

hi, guys. Suppose i have Gaussian variable X and mean 'u' and 'σ^2', how do i use efrc to find the probability

thank you for the help

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Answer 1

Star Strider 2016-1-25

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https://ww2.mathworks.cn/matlabcentral/answers/265132-gaussian-probability-function-matlab#answer_207371

在 MATLAB Online 中打开

From the documentation, the erf function could be preferable:

u = 0.5;                            % Create Data
s = 0.2;
x = 0.8;
v = (x-u)/(s*sqrt(2));
p = (1 + erf(v))/2                  % Use ‘erf’
q = normcdf(x, u, s)                % Check With ‘normcdf’
p =
   933.1928e-003
q =
   933.1928e-003

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Star Strider 2016-1-25

在 MATLAB Online 中打开

Using erfc needs only slightly different code (again from the documentation) to produce the same result:

u = 0.5;                            % Create Data
s = 0.2;
x = 0.8;
v = (x-u)/(s*sqrt(2));
p = erfc(-v)/2                      % Use ‘erfc’
q = normcdf(x, u, s)                % Check With ‘normcdf’
p =
   933.1928e-003
q =
   933.1928e-003

Star Strider 2016-1-26

My pleasure.

Please do not use mean as a variable name! It is an important MATLAB function that you will want to use later. Using it as a variable ‘overshadows’ its use as a function, so you won’t be able to use the function.

If the noise is normally distributed with a known mean and standard deviation, you would use the erfc code in my previous Comment to find the probability. That’s how I would calculate it, anyway.

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