swarmchart関数はどうでしょう
x1 = ones(1,50);
x2 = 2 * x1;
y1 = [rand(1,30)*2-1 ones(1,10) -ones(1,10)];
y2 = [rand(1,30)*2-1 ones(1,10) -ones(1,10)];
swarmchart(x1,y1,25,'k','filled','XJitter','rand','XJitterWidth',0.5);
hold on
swarmchart(x2,y2,25,'k','filled','XJitter','rand','XJitterWidth',0.5);
yline(0,'--');
line([0.75,1.25],[mean(y1) mean(y1)],'Color','k');
line([1.75,2.25],[mean(y2) mean(y2)],'Color','k');
hold off
