Class Mid points
This is very significant values which mark the center of a provided class. They are acquired by adding together the two limits of a provided class and dividing the result by 2.
Class interval or width
It is the difference between a lower class boundary and upper class boundary. The value normally measures the length of a provided class.
|
Age (yrs)
|
No. of Students (f)
|
mid points (x)
|
x-a = d
|
D/c = u
|
fu
|
|
15 - 19
|
21
|
17
|
-15
|
-3
|
-63
|
|
20 - 24
|
35
|
22
|
-10
|
-2
|
-70
|
|
25 - 29
|
38
|
27
|
-5
|
-1
|
-38
|
|
30 - 34
|
49
|
32(A)
|
0
|
0
|
0
|
|
35 - 39
|
31
|
37
|
+5
|
+
|
31
|
|
40 - 44
|
19
|
42
|
+10
|
+2
|
38
|
|
|
193
|
|
|
|
-102
|