Answer:
12
Step-by-step explanation:
The mean is also the average.
Add up all the number of students all together:
12+13+14+9
48
Now, Divide the total amount of students (48) by the amount of numbers you added (in this case, 48/4 because we added 4 numbers wich are 12+13+14+9)
The average amount of students is 12
