找到3小时的平均数据

Question

在下面的代码中，每个y的持续时间为8分钟。一旦我生成了Powerr矩阵，我就拥有了我需要的但我如何做3小时平均值？我应该在for循环中做什么，或者一旦我生成Powerr矩阵，我仍然能够找出我的数据的3小时平均值吗？提前谢谢。

fid = fopen([directory '001/listing.txt'],'r');
   tline = fgetl(fid);
       ii = 0;
   while (tline ~= -1)
            if (length(tline) == 0)  
               continue
            end
            ii = ii + 1;
            file_names(ii,:)=tline;  % create file names in matlab data worksapace
            year(ii) = str2num(tline(11:14));
            month(ii) = str2num(tline(15:16));
            day(ii) = str2num(tline(17:18));
            hour(ii) = str2num(tline(20:21));
            min(ii) = str2num(tline(22:23));
            sec(ii) = str2num(tline(24:25));
            tline = fgetl(fid);
   end   
   fclose(fid);
   timestamp = datenum(year,month,day,hour,min,sec);




%--------window applied is Hanning window--------                                              
   nfft = 4096;                              % |
    hanning_window = hanning(nfft); % |
%-------------------------------------------------
    timestamp = datenum(year,month,day,hour,min,sec);


tic
profile on
warning('off','MATLAB:audiovideo:wavread:functionToBeRemoved');
    neglect_the_first_few= 5;
    lastfile = 20;
    Powerr = zeros(2049,20);
%     fr = zeros(2049,1);
   count =[];
    parfor count = neglect_the_first_few + 1 :lastfile
    warning('off','MATLAB:audiovideo:wavread:functionToBeRemoved');

                y= [];
%             for inputfile = infiles'
                fn = [directory '/001/' file_names(count,:)];

                 [y,fs,nbits] = wavread(fn,'native');   
                disp(['sampling freq is ',num2str(fs),' hz. length of y is ',num2str(size(y)),'filenumber is ',num2str(count)])

%             end

            y = y- mean(y);
             Y = double(y).*(1.49365435131571e-07);%CONVERSION - volts per bit for 24bit channel
%             clear y;

             nooverlap =[];%number of overlapped segments set to zero on Nov20th 2017
            [Poww,fr] = pwelch(Y,hanning_window,nooverlap,nfft,fs);%no overlap taken into account%



            Powerr(:,count) = Poww;
            freq(:,count)= fr;

    end