Plot title in bold and larger size

using Matlab syntax: FontWeight, FontAngle,..
plot([1,4,3,6,12,20],'.-')
title('Prediction','FontWeight','bold','fontsize',16); % title bold and size 16
xlabel('time','FontAngle','italic');   % write xlabel in italic
ylabel('intensity','FontWeight','bold');   % write ylabel in bold

see more Matlab text properties

How to print two lines:  title & subtitle?

use a cell array:

 title( {'Title';'subtitle'} )

text properties can be added by \tex syntax:  \bf for bold; \it for italic; ...