dataframe - Total Mean & Mean by groups in R with dplyr

Question

Assume I have a dataset something like

df <- data.frame(dive=factor(sample(c("dive1","dive2"),10,replace=TRUE)),speed=runif(10))

Now my goal is to find " Total mean of the data" and "Mean by Subgroups in R" in same data. So, I can say I should get something like

#    dive  Total_Mean   speed
# 1 dive1   0.52        0.5790946
# 2 dive2   0.52        0.4864489

I am using a code

df%>% summarise(avg=mean(speed))%>%
group_by(dive)%>%
summarise(Avg_group=mean(dive))

Which is wrong I know, So all I am seeking is how can I group by and open my data gain in dplyr for performing different operations at different time

Answer 1

Try this:

df %>% 
   mutate(avg=mean(speed)) %>% 
   group_by(dive) %>% 
   summarise(Avg_group=mean(speed),Total_Mean=first(avg))