try
data = cell(4:24);
catch ME
disp(ME.message);
end
If you want each cell of data to contain {'AD';'ED';'FA';'DE'}:
data = cell(4,24);
data(:) = {{'AD';'ED';'FA';'DE'}};
disp(data);
If instead you want each column of data to be {'AD';'ED';'FA';'DE'}:
data = repmat({'AD';'ED';'FA';'DE'},1,24);
disp(data);