For multiple linear regression, Predictor creates assumptions for the independent variable forecast values only. This is because the independent variable values are simple value cells, but the dependent variable values are formula cells that are a function of the independent variables.
To see the variability of the dependent variable, select the pasted formula cells and define them as Crystal Ball forecast cells. (To do this, select Define, and then Define Forecast.) More likely, you will want to create one formula cell that represents the sum of the data in the dependent variable cells and define that formula cell as a Crystal Ball forecast.