function meandiffplot(x, y, md, ds, dq, k, nrows)
% Plot histogram of data sets and of null hypothesis for differences in mean.
%
% meandiffplot(x, y, md, ds, dq, k, rows);
%
% Arguments:
%   x: vector with the samples of the x data set.
%   y: vector with the samples of the y data set.
%   md: difference of means of the two data sets.
%   ds: vector containing the differences of the means of the resampled data sets
%   dq: minimum difference of the means considered significant.
%   k: current row for the plot panels.
%   nrows: number of rows of panels in the figure.

  %% (b) plot histograms:
  subplot(nrows, 2, k*2-1);
  bmin = min([x; y]);
  bmax = max([x; y]);
  bins = bmin:(bmax-bmin)/20.0:bmax;
  [xh, b] = hist(x, bins);
  [yh, b] = hist(y, bins);
  bar(bins, xh, 'facecolor', 'b')
  hold on
  bar(bins, yh, 'facecolor', 'r');
  xlabel('x and y [mV]')
  ylabel('counts')
  hold off

  %% (f) pdf of the differences:
  [h, b] = hist(ds, 20);
  h = h/sum(h)/(b(2)-b(1));           % normalization

  %% plot:
  subplot(nrows, 2, k*2)
  bar(b, h, 'facecolor', 'b');
  hold on;
  bar(b(b>=dq), h(b>=dq), 'facecolor', 'r');
  plot([md md], [0 4], 'r', 'linewidth', 2);
  xlabel('Difference of means [mV]');
  ylabel('pdf of H0');
  hold off;
end