1.In Difference in Difference Estimation we observe the treatment and control groups over _____ period(s)

A. 4 B. 1 C. 3 D. 2

2.The following tools are used in Machine Learning with the exception of:

A. all the above are Machine Learning Tools B. LOESS C. Regression Trees D. Classification Trees

3.The ultimate goal of Machine Learning is to

A. collect data B. find the mean of the variables C. none of these D. find patterns in the data.