diff --git a/datetimes.Rmd b/datetimes.Rmd
index 5dc915c..5bd1129 100644
--- a/datetimes.Rmd
+++ b/datetimes.Rmd
@@ -251,7 +251,7 @@ flights_dt %>%
   mutate(minute = minute(dep_time)) %>% 
   group_by(minute) %>% 
   summarise(
-    avg_delay = mean(arr_delay, na.rm = TRUE),
+    avg_delay = mean(dep_delay, na.rm = TRUE),
     n = n()) %>% 
   ggplot(aes(minute, avg_delay)) +
     geom_line()