confidence bands for the sum of two rvs (from pool)

[rbgentile]

For EViews 9 -- Trying to calculate confidence bands for a forecast of the weighted average of wages across two states, based on a pooled estimates for fifty states. EViews provides standard errors and confidence bands for a specified confidence level for the individual rvs. Is there a way to obtain the necessary information -- sample sizes, the variances and covariance of the rvs -- to calculate the standard errors for the weighted average?

[startz]

The variance of w_1*x + w_2*y is w_1^2*var(x) +w_2^2*var(y) + 2*w_1*w_2*cov(x,y)