Go to the link below to download survival times for 87 people with lupus nephritis. They were followed for 15+ or more years after an initial renal biopsy. The duration variable indicates how long the...

Go to the link below to download survival times for 87 people with lupus nephritis. They were followed for 15+ or more years after an initial renal biopsy. The duration variable indicates how long the patient had the disease before the biopsy; construct the Kaplan-Meier estimator for survival, ignoring the duration variable.