The current document for A4T says that every metric is available, including any custom or calculated metrics that are built-in in Analytics. However, when we select the calculated metrics as the primary goal for an activity in Target, the lift and confidence calculations are not available in Target and Analytics.
Edit: While this idea is being considered for future, it would be awesome if Adobe can share how to build a calculated metric in Adobe Analytics for confidence interval calculation. I understand that the calculated metric builder has some advanced formula and functions but how to use them for the confidence calculation?