I have a data frame with a list of IDs and other variables like so:
Student_ID Score
6 94
2 63
6 100
7 44
6 97
2 67
I would like to create another data frame that consists of just the Student_ID and average score like this:
Student_ID Avg_Score
2 65
6 97
7 44
The actual data set is much larger, of course.
You can use dplyr package:
df %>% group_by(Student_ID) %>% summarise(Avg_Score = mean(Score))
# # A tibble: 3 x 2
# Student_ID Avg_Score
# <int> <dbl>
# 1 2 65
# 2 6 97
# 3 7 44
You can also use aggregate in base R:
aggregate( Score ~ Student_ID, df, mean) #column name will remain as "Score"
# Student_ID Score
# 1 2 65
# 2 6 97
# 3 7 44
