[18 Marks] A trial was conducted on the effectiveness of a new cream to treat a skin condition. 100 sufferers applied the cream daily for four weeks or until their symptoms disappeared if this happened sooner. Some of the sufferers left the trial before their symptoms disappeared. The following data were collected. Number of sufferers Day symptoms disappeared Day they Number of left the sufferers trial 2 6 3 2 1 7 1 10 1 10 3 13 2 14 1. Describe two types of censoring that are present and state to whom they apply. ii. Calculate the Nelson-Aalen estimate of the survival function for this trial. MS338-Actuarial Modelling Semester 1 Examinations 2020/2021 Page 2 of 6 af64e738 iv. Sketch the survival function, labelling the axes. Estimate the probability that a person using the cream will still have symptoms of the skin condition after two weeks