Use the following code. You replace your data with DataY.
figure ('Position', [293,243,900,420]);
DataX = (20:30:620)';
DataY = [
2.5 1.6
3.0 2.0
3.5 2.2
3.6 2.3
4 2.5
4.3 2.7
4.2 2.6
2.5 1.6
3.0 2.0
3.5 2.2
3.6 2.3
4 2.5
4.3 2.7
4.2 2.6
2.5 1.6
3.0 2.0
3.5 2.2
3.6 2.3
4 2.5
4.3 2.7
4.2 2.6
];
BarChart = bar (DataX, DataY);
xticks (DataX);
set (BarChart, {'FaceColor'}, {[0,0,1];[1,1,0]});
