Thread: Measures of central tendency

The frequency distribution of the verbal scores on the SAT test for students at a high school is shown below

scores number of students
200-250 9
250-300 14
300-350 23
350-400 30
400-450 33
450-500 28
500-550 18
550-600 12
600-650 7
650-700 3
700-750 1
750-800 1


What is the mean of the verbal scores at the high school

I know there are 179 student I added them up

Then I guess I have to find the sum of all the scores which I got to be 70175

What I did for example was 200+250 divided by times nine to get 2025

then I did 70175/179 But I get the wrong answer.

Pick the number half way in each class interval