0 Replies Latest reply: Dec 4, 2012 4:43 AM by eduqlikview

EWMA - Regelkarte

Hey!

I would like to plot the following expression but I have some problems with the second therm:

$z_i = \lambda \bar x_i + \left ( 1 - \lambda \right)z_{i - 1}$.

Here I copy the explanation of the formula:

"The EWMA chart computes successive observations zi by computing the rational subgroup average, $\bar x_i$, and then combining that new subgroup average with the running average of all preceding observations, zi - 1, using the specially–chosen weight, λ."

My Data looks like this:

 Date Value 2012.01.03 16:03:55 0,41 2012.01.03 20:31:43 0,434 2012.01.03 23:13:58 0,42 2012.01.04 13:56:06 0,431 2012.01.04 16:21:06 0,455 2012.01.04 22:14:28 0,45 2012.01.04 22:20:31 0,437 2012.01.04 22:26:45 0,448 2012.01.04 22:35:22 0,437 2012.01.04 23:16:09 0,449 2012.01.11 10:10:07 0,449 2012.01.11 10:37:04 0,422

The subgroups must be "days".

Thank you very much!!! This chart is driving me crazy!

Eduardo