A prospectus study with a 2-year (24 month) follow up was conducted. Results are shown in the table for individuals who either died or were censored before the end of the follow-up period.

Survival data for 24 participants of a hypothetical prospective study.
Follow- up time (months)	Event
2	Death
4	Censored
7	Censored
8	Death
12	Censored
15	Death
17	Death
19	Death
20	Censored
23	Death

1a. Using the data from the table, for all deaths calculate (1) the probability of death at the exact time when each death occurred. (2) The probability of survival beyond the time when each death occurred. (3) the cumulative probabilities of survival.

b. What is the cumulative survival probability at the end of the follow-up period?

c. Using arithmetic graph paper, plot the cumulative probabilities of survival.

d. What is the simple proportion of individuals apparently surviving (i.e., not observed to die

through the end of the study's observation period?