# Find the average in a window of random variables

5 views (last 30 days)
Tino on 28 May 2020
Edited: Adam Danz on 22 Aug 2020
Hi pls
I have 10 random variables ( 2,4,5,6,3,4,5,7,8,6)
I want to write a matlab code that will do this computation using 5 window length ( k = 5)
1st window length (2,4,5,6,3)
2nd window length ( 4,5,7,8,6)
then I can find the average of each windom numbers
1st window average = 4
2nd window average = 6
darova on 28 May 2020

Adam Danz on 28 May 2020
Edited: Adam Danz on 22 Aug 2020
Matlab has movmean() but it I don't think it can move by groups of n elements.
This demo below computes a moving average for values [1:n, 1*n+1:2*n, 2*n+1:3*n, 3*n+1:4*n, etc...]
If the number of data points is not dividible by n, the data are padded with NaN values and the last average will only consider non-nan values.
data = 1:22; % Demo data
winSz = 5; % Window size
% Reshape data into matrix.
% NOTE: 'data' must contain a number of element divisibly by 'winSz'.
% Otherwise, 'data' will be padded with NaN values so that it is
% divisible by 'winSz'.
if rem(numel(data),winSz)>0
nanAppend = nan(winSz - rem(numel(data),winSz),1);
else
nanAppend = [];
end
dataMat = reshape([data(:); nanAppend], winSz, []);
movingAverage = mean(dataMat,1,'Omitnan');
% Result
% movingAverage =[3 8 13 18 21.5]
To compute the means of groups that share endpoints (e.g. indices 1:5, 5:9, 9:13, ...), see this answer.

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