use_fh_survival: ###########################################################################
Get the parameter values using the survival analysis method FH
Description
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Get the parameter values using the survival analysis method FH
the independent variable (column name in data file)
covariates
list of covariates
timevar_survival
time variable for survival analysis, default is NA
Value
the results of the regression analysis
Details
This function is for survival analysis using FH.
This plots the cumulative survival function for each combination of covariate
If the covariate is numeric, R takes it as different levels.
The plot uses the returned list of survfit and extracts the time and the
strata from summary of the fit
(implemented in plot_return_survival_curve function)