How to calculate the benefit of each additional LHS value arules

Question

I need to know how to do a simple calculation but cant remember how to do it.

If i have completed a market basket analysis and the results are as follows:

Bread => Milk: and the confidence = .6

Oreos => Milk: and the Confidence = .5

What is the confidence for:

bread, Oreos => Milk: what is the Confidence =?

Answer 1

You cannot tell from the information you have. You need to go back to the data and do some more counting. You need to know how often bread and Oreos occur together.