random number with specific variance in matlab

To generate random numbers with a specific variance in MATLAB, you can use the randn() function to generate random numbers from a normal distribution with mean 0 and variance 1. You can then adjust these numbers to have the desired variance by scaling and shifting them as necessary.

Here's an example that generates a vector of 100 random numbers with a variance of 2:

main.m
% Desired variance
desiredVar = 2;

% Generate 100 random numbers from a normal distribution with mean 0 and variance 1
x = randn(1, 100);

% Scale and shift the numbers to have the desired variance
y = sqrt(desiredVar) * x + mean(x);
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In this example, the sqrt() function is used to scale the numbers by the square root of the desired variance and the mean() function is used to shift them to have a mean of 0. You can adjust these parameters as necessary to achieve the desired variance and mean for your specific use case.