the math of movmean

Hello

how movmean works exactly if movemean(DATA,5) is that means that it will take the first five number and divide it by 5 and then take the next 5 number and divide it by 5 and so on i know that not the case because i calculate it and the numbers didn't match plz help

Answer 1

[Walter Roberson]

help movmean

Y = movmean(X,K) for a vector X and positive integer scalar K computes

a centered moving average by sliding a window of length K along X. Each

element of Y is the local mean of the corresponding values of X inside

the window, with Y the same size as X. When K is even, the window is

centered about the current and previous elements of X. The sliding

window is truncated at the endpoints where there are fewer than K

elements from X to fill the window.

So it does not take the first 5 and then move over 5 and take those and so on:

[mean(x(1:3))
 mean(x(1:4))
 mean(x(1:5))
 mean(x(2:6))
 mean(x(3:7))
 ....
 ]

and ending at x(end-2:end)

Answer 2

[Matt J]

If if the data looks like,

DATA=[x1,x2,...xn ,   a,b,c,d,e,      y1,y2,....,ym]

then movemean(DATA,5) will replace c with mean([a,b,c,d,e]). In other words, it will center a window of length 5 at the current point and average the elements in that window. For elements near the edge of the array, there will be missing elements. The handling of the missing elements depends on what you give for the 'Endpoints' input parameter.