Maths

278 MATHEMATICS
n
2
Here n = 100, which is even. The median will be the average of the
2
n th and the
✁
✂ ☎ 1 th observations, i.e., the 50th and 51st observations. To find these
✄
✝ ✆
observations, we proceed as follows:
Table 14.10
Marks obtained
Number of students
20 6
upto 25 6 + 20 = 26
upto 28 26 + 24 = 50
upto 29 50 + 28 = 78
upto 33 78 + 15 = 93
upto 38 93 + 4 = 97
upto 42 97 + 2 = 99
upto 43 99 + 1 = 100
Now we add another column depicting this information to the frequency table
above and name it as cumulative frequency column.
Table 14.11
Marks obtained Number of students Cumulative frequency
20 6 6
25 20 26
28 24 50
29 28 78
33 15 93
38 4 97
42 2 99
43 1 100