MATLAB: Random numbers between a and b with specified mean and variance

random

I am using a + b*rand() to create uniformly distributed variables between [a,b]. But I want to create the same with a specified mean and variance. Is there a way to do so in matlab?

Best Answer

1) a + b*rand() creates a value between a and a+b, not between a and b.

2) The values will have a uniform distribution with mean and variance fixed depending on a and b. If you want other mean and variance values then you either need a different a and b or you need a different distribution. Please specify what exactly you want.

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MATLAB: Generate random number between -1 and 1 with specified mean and variance

Hi, You did not state what distribution you want the random numbers to follow. From your use of randn() in your post, I'm assuming Gaussian. In that case you can scale randn() by a factor that will reduce the variance so that the numbers lies between [-1,1].

For example, since a Gaussian random variable is expected to be essentially the mean +/- 3*standard deviation (with probability close to 1), you can use

x = (1/3)*randn(100,1);

to generate a Gaussian-distributed random sample that essentially lies with +/- 1.

You can use rand():

r = -1 + 2.*rand(100,1);

to generate a uniformly-distributed random sample on [-1,1].

Wayne

MATLAB: Question on how to calculate the variance and then standard deviation on an interval from a to b with 100 samples of size 225 random numbers

Why not use mean(), var(), and std()?

Your c is not using any actual values. You need to do something like

data = a + (b-a)*rand(1, nsamples);
cMean = mean(data)
cStdDev = std(data)

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Related Solutions

MATLAB: Generate random number between -1 and 1 with specified mean and variance

MATLAB: Question on how to calculate the variance and then standard deviation on an interval from a to b with 100 samples of size 225 random numbers

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