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I've been learning about survival curves and was working through David Collett's modelling survival data book. In particular I derived the Greenwood formula for the standard error of the survival function at a particular time t, and manually calculated the survival function and 95% confidence limits for an example given in the book - page 28 (getting the book's answers).
When I came to do it in R using survfit (and setting error = "greenwood" just to be safe) I got the same survival function, the same standard errors but different upper and lower 95% confidence bounds. The one's I got using R were somewhat wider than the results in the book.
Below is the data I put into R (as a tab separated .txt file). I call the function as: