Question

Consider the following distribution:
Marks
O or more
10 or more 20 or more 30 or more 40 or more 50 or more

Number of
Students
63
58
55
51
48
42
(a) Calculate the frequency of class 30 - 40.
(b) Calculate the class mark of the class 10 - 20.
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Answer 1

Answer:

The given table in question is more than frequency distribution table.

We are going to form frequency distribution table :

Marks No.ofstudents

0−10 63−58=5

10−20 58−55=3

20−30 55−51=4

30−40 51−48=3

40−50 48−42=6

50−60 42

(a) The frequency of class 30−40=3

(b) The class mark of the class 10−20

$\huge \frac{10 + 20}{3} = 15$