diff --git a/transform.Rmd b/transform.Rmd
index 4dcc444..663aa99 100644
--- a/transform.Rmd
+++ b/transform.Rmd
@@ -592,7 +592,7 @@ The story is actually a little more nuanced. We can get more insight if we draw
 delays <- not_cancelled %>% 
   group_by(tailnum) %>% 
   summarise(
-    delay = mean(arr_delay, na.rm = TRUE),
+    delay = mean(arr_delay),
     n = n()
   )