One approach:
x = 1:10; % Create Data (Independent Variable)
V1 = randn(1, 10); % Create Data (Row Vectors)
V2 = randn(1, 10);
V12_sd = std([V1; V2]); % Standard Deviation
V12_mean = mean([V1; V2]); % Mean
figure(1)
errorbar(x, V12_mean, V12_sd)
grid
