Question 1. Using the data from the WHAS for grouped cohort 1 (1975 and 1978), with length of follow up as the survival time variable and status at last follow up as the censoring variable, do the following:

(a) Fit the proportional hazards model containing age, sex, peak cardiac enzymes, left heart failure complications and MI order.

(b) Assess the significance of the model using the partial log likelihood ratio test. If it is possible in the software package, assess for the significance of the model using the score and Wald tests. Is the statistical decision the same for the three tests?

(c) Using the univariate Wald tests, which variables appear not to contribute to the model?

(d) Fit the reduced model in problem 1(c) using the Breslow, Efron and exact methods for tied survival times. Compare the estimates of the coefficients and standard errors obtained from the three methods for handling tied survival times. Are the results similar or different?

(e) Estimate the baseline survivorship function for the model fit in problem 1(c), Graph the estimated baseline survivorship function versus survival time. What covariate pattern is the "baseline" subject for the fitted model.

(f) Repeat problem 1(c) using age centered at the median age of 65 years. Explain why the range of the estimated survivorship functions in problems 1(c) and 1(f) are different.

(g) Using the model fit in problem 1(f) estimate the value of the survivorship function for each subject at his or her respective observed value of time

please explain all and use R code

this is a hw question I need help and Im stuck with all the data is in R already

I need hw help on this question