compute_CI: Function to generate correlated prediction intervals from a...
In MortalityGaps: The Double-Gap Life Expectancy Forecasting Model

Function to generate correlated prediction intervals from a mvrnorm

1	compute_CI(pred_results, M1, M2, M3, h, iter, ci, cou)

`pred_results`	An object containing predicted values
`M1`	Model 1 - Linear regression bp-life-expectancy.
`M2`	Model 2 - Time-series D-gap.
`M3`	Model 3 - Sex-gap.
`h`	The number of steps ahead for which prediction is required.
`iter`	Number of iterations. Default: 500
`ci`	Confidence levels. Default: c(0.8, 0.95)
`cou`	Country name.