How to compute Expectation in MatLab?

Hello Guys,

I need to compute E{x^4} in MatLab (x is vector). Can it be done by taking the mean value of x^4 (each element of x exponent 4).

Thanks for the help. Regards

Answer 1

[Stephen23]

Many basic operators in MATLAB are treated as matrix operations, including multiplication , division ,and power operators.

When you wish to perform the same operation element-wise, then you can use the element-wise syntax. For example matrix multiplication is A*B, whereas multiplication of corresponding array elements is A.*B .

In your example, this means you can simply use the element-wise power function:

x.^4

which operates on the whole vector at once. Handy! You might like to read this too:

http://www.mathworks.com/help/matlab/matlab_prog/vectorization.html

Answer 2

[Star Strider]

That is how I would do it, using element-wise exponentiation:

Ex4 = mean(x.^4);