Damith - where is the line (or lines?) of code that is used to plot the data via scatter? Unless you mean the line of code
ht = text(Ob_All_avg, WGEN_All_avg, num2str(k));
which displays the numbers from 1 through 6 at coordinates defined by Ob_All_avg and WGEN_All_avg which does plot the numbers using the colormap defined by jet(n).
If you want these numbers just in black then just remove the lines
cmap = jet(n); % builtin colormap; could choose another...
C = mat2cell(cmap, ones(1, size(cmap, 1)), 3); % reshape for 'set'
and later
set(ht, {'Color'}, C)
which sets the colour of the text (numbers) to that of the colour map. With these three lines gone, the default colour of black should be used.
