You can try using an intermediate variable to store the information you load from each file. On a quick thought, you must do something like this:
files = dir('*.mat'); % Get all of the files properties with a .mat extension
% Load the first file to know the length of the signal.
% If you already know it, you may skip this,
% assign accumulativeVector the known size (1351 in your case)
% and run the loop beginning in 1 (and not in 2).
load(files(1).name);
accumulatedVector = x;
% Sweep the rest of the files.
for i=2:length(files)
load(files(i).name); % Load the files. Notice how "eval" is not needed.
accumulatedVector = accumulatedVector + x; % x is the name of the variable.
end
accumulatedVector = accumulatedVector ./ length(files); % Average.
EDIT
I would like to add that in the first line, files is a structure containing the information (properties) of all the files in your current directory with a .mat extension.
When you refer to files(i).name (for example), you are extracting the property name (the file's name) of the file i of the structure files. That is the beauty of this =) . Try it and let me know if it works!
