Comparing Weibull and Log-Normal Model I

In this exercise, we want to add the correct survival probabilities to a data frame. This data frame will be used to plot the survival curves. surv_wide is a wide data frame containing hormonal therapy information and the survival curves for the Weibull and log-normal models.

The survival, survminer, and reshape2 packages and the GBSG2 data are loaded for you in this exercise.

This exercise is part of the course

Survival Analysis in R

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Exercise instructions

Melt the data frame into long format.
Use surv_long$surv_id to add the correct survival probabilities surv to the data frame.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Melt the data.frame into long format.
surv_long <- melt(surv_wide, ___ = c("horTh", "dist"), ___ = "surv_id", ___ = "time")

# Add column for the survival probabilities
surv_long$surv <- surv[as.numeric(surv_long$___)]

# Add columns upper, lower, std.err, and strata contianing NA values
surv_long[, c("upper", "lower", "std.err", "strata")] <- NA

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