Question

Find the mean from the following frequency distribution of marks at a test in statistics:

Marks (x):	5	10	15	20	25	30	35	40	45	50
No. of students (f):	15	50	80	76	72	45	39	9	8	6

Answer 1

Let the assumed mean beand .

We know that mean,

Now, we have.

Putting the values in the above formula, we get

Hence, the mean marks is 22.075.