diff --git a/README.md b/README.md
index 123c08e..e8e8a68 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ library("GPCERF")
   # exposure values
   w.all = seq(0,20,0.1)
 
-  data.table::setDT(sim.data)
+  data.table::setDT(sim_data)
 
   cerf_gp_obj <- estimate_cerf_gp(sim.data,
                                   w.all,