When I run:
CO2 %>%
group_by(Plant, Type, Treatment) %>%
summarize(count = n()) %>%
glimpse()
...I see the following output:
Observations: 12
Variables: 4
Groups: Plant, Type [?]
$ Plant <ord> Qn1, Qn2, Qn3, Qc1, Qc3, Qc2, Mn3, Mn2, Mn1, Mc2, Mc3, Mc1
$ Type <fct> Quebec, Quebec, Quebec, Quebec, Quebec, Quebec, Mississippi…
$ Treatment <fct> nonchilled, nonchilled, nonchilled, chilled, chilled, chill…
$ count <int> 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
...what does the "[?]" signify in the line "Groups: Plant, Type [?]" ?
Why do we not instead see: "Groups: Plant, Type, Treatment" since those are the 3 fields against which we grouped the data?