Writing bar notation/overline and sigma signs in matlab

Dear All, I am performing some calculations that require displaying mean, sum using standard statistical parameters like subscript(x1), bar(x1) and sigma(x1). Don't know how these characters are coded in Matlab. Please help.

x1 = [9, 5, 6, 1, 11]; % want x1 displayed as x(subscript1)
y1 =[17, 8, 13, 20, 16]; %want y1 displayed as x(subscript1)
A = mean(x1)% want A to be bar(x1)
B = mean(y1)% want B to be displayed as bar(y1)