how to set my graphic size to (w:h=550:400) now my graph size is 560:420 (automatic)

[ day_number, daily_rain ] = DailyRain( RainData, 2010, 1);
andemande = plot( day_number, daily_rain,'-ok' );
set(andemande,'LineWidth',1);
day_numbermax = max(day_number);
day_numbermin = min(day_number);
datetick('x','dd-mmm','keepticks')
grid on;
ylabel('Akumulasi Curah Hujan (mm)')
xlabel('Hari')
xlim([day_numbermin day_numbermax])