answer all questions with explanation

In September 1997, 100 students were admitted to the Dental Hygienist Program, a two-year program. Seventy-two of them completed the first year, and 55 completed both years of the program. In September 1998 an- other 100 students were admitted to the same program. and 57 completed the first year. Use the Kaplan-Meier estimator to estimate the probabil- ity of a student, admitted in September 1999, completing the two-year program