Question

find the mean?

I know how to find the mean but it's not working on this one, what am I doing wrong

Answer 1

70-79

Answer 2

you have to interpret the table. You have to find the average of 30 numbers.
The table says 3 of the students have a grade between 90 and 99. It also says "assume the grade is the middle value". In other words, assume you have 3 95's

to find the average of the 30 numbers, we add them up and then divide by 30.
so far, we have 95+95+95 or 3*95= 285

you need the rest of the numbers...