Check out the way state-of-the-art machine learning modeling is possible now in Excel for any spreadsheet. See the example of predicting Rio 2016 gold medal counts.
Each spreadsheet is a probabilistic generative model, and we allow you to express uncertainty in some cells using functions like GAUSSIAN, NEAR, CHOICE, and also incorporate already known data using function ACTUAL.
Then, the plugin generates valid scenarios given all assumptions and actuals. You can explore scenarios, see averages (expected values), enhance the model, and repeat it until you are satisfied with the prediction quality.