Probabilistic Definition

a. Double click on the ‘Fuel price’ node to open its object window

b. Change the identifier to ‘Price’

c. Type ‘$’ in the ‘Units’ field. Press ‘Tab’ key. In the ‘Description’ field, type ‘price of a gallon of gasoline’.

d. Click the ‘expr’ button. Select ‘Distribution’. The object finder should appear. In the object finder, scroll down, and select ‘Normal’. Type ‘1.19 and 0.1’, in the ‘mean and sttdev’ window. Click ‘ok’. Now the definition for the node should be set to ‘Normal(1.19,0.1)’

a. Bring up the object window. There are two ways to do this

• First, Select fuel cost node. Click ‘object button’ from the tool palette. The object window should appear. Close the object window.
• Now try Double clicking on the ‘Fuel cost’ node. Object window should appear.

b. Click on the ‘units’ field. Type ‘$/year’. Press tab key. In the ‘Description’ field, type ‘Annual cost of fuel’. Press tab key.

Enter the mathematical expression in the ‘Definition’ fieldClick on the ‘Definition’ field. A cross and check box, together with ‘inputs’ button should appear. Click ‘inputs’ button. Select ‘Fuel price’. Type ‘*’. Select ‘miles per year’. Type ‘/’. Select ‘Miles per gallon’. The definition field now should be ‘Fuel_Price*Mpy/Mpg’

c. Click the ‘Diagram’ button. You should return to influence diagram