library("hazreg")
dat=read("nursing.dat")
t = dat[,1]
delta = dat[,2]
age = dat[,3]
gender = dat[,4]
married = dat[,5]
limit = matrix(rows(dat), 1)*90 ; transform AGE
agespline = min(age~limit,2) - 65
z = agespline~gender~married
{data, ties} = hazdat(t, delta, z) ; prepare data
{betahat, betak, ck}=hazbeta(data) ; estimate beta
betahat
{ll, ll1, ll2} = hazregll(data, betahat)
sigma = inv(ll2) ; estimate SE(beta)
sigma
{ttest1, val1, df1, pval1} = haztest(data, (0|1|1))
ttest1
{ttest2, val2, df2, pval2} = haztest(data, (1|0|1))
ttest2
{ttest3, val3, df3, pval3} = haztest(data, (1|1|0))
ttest3