Using data from grouped cohort 1 (1975 and 1978) from the Worcester Heart Attack Study, compute the following using SAS:

(a) The Kaplan-Meier estimate of the survivorship function for each gender.

(b) Pointwise 95 percent confidence intervals for the survivorship functions estimated in part (a).

(c) Point and 95 percent confidence interval estimates of the 25th, 50th and 75th percentiles of survival time distribution for each gender. (d) The mean survival time for each gender. (e) A graph of the estimated survivorship functions for each gender computed in part (a) along with the pointwise 95 percent limit computed in part (b).

Description of the variables in the WHAS show in Table 1.4 of a Hosmer, D.W. and Lemeshow, S. (1998) Applied Survival Analysis: Regression Modeling of Time to Event Data, John Wiley and Sons Inc., New York, NY

Data are in file WHAS.DAT n = 481

Variable Description Codes / Units

ID Identification Code 1 - 481

AGE Age (per chart) years

SEX Gender 0 = Male 1 = Female

CPK Peak Cardiac Enzyme International Units (iu)

SHO Cardiogenic Shock 0 = No Complications 1 = Yes

CHF Left Heart Failure 0 = No Complications 1 = Yes

MIORD MI Order 0 = First 1 = Recurrent

MITYPE MI Type 1 = Q-wave 2 = Not Q-wave 3 = Indeterminate

YEAR Cohort Year 1 = 1975 2 = 1978 3 = 1981 4 = 1984 5 = 1986 6 = 1988

YRGRP Grouped Cohort Year 1 = 1975 & 1978 2 = 1981 & 1984 3 = 1986 & 1988

LENSTAY Length of Hospital Stay Days Days in Hospital

DSTAT Discharge Status 0 = Alive from Hospital 1 = Dead

LENFOL Total Length of Follow-up Days from Hospital Admission

FSTAT Status as of Last 0 = Alive Follow-up 1 = Dead