Solved: Re: Summation for empirical dispersion

ptc-5820280 · ‎May 18, 2014

Hi. How do I write and describe this summation:

in Mathad Prime 3.0?

P.S. Dont mind the second X in brackets, I can't find a way to describe Xi.

Werner_E · ‎May 18, 2014

Here you are. As already written you have to use the vector index you get either from the ribbon menu or by typing [

In case you don't know - Mathcad has a lot of built-in statistical functions, standard deviation (you are calculating the square of it) is one of them, so you may use it. See attached sheet.

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Werner_E · ‎May 18, 2014

X should be a data vector consisting of n elements. You have to use the matrix/vector index for Xi (writing X[i), not the literal index you get with Ctrl&-.

You might also consider to sum from 0 to n-1 rather than from 1 to n or change the system variable ORIGIN to 1.

If this doesn't help come back and privide a Mathcad sheet to work on.

ptc-5820280 · ‎May 18, 2014

I'm really not sure how does data vector work. I've attached what I've came up so far. Could you solve this for me?

Werner_E · ‎May 18, 2014

Here you are. As already written you have to use the vector index you get either from the ribbon menu or by typing [

In case you don't know - Mathcad has a lot of built-in statistical functions, standard deviation (you are calculating the square of it) is one of them, so you may use it. See attached sheet.