Page 64 - DECO504_STATISTICAL_METHODS_IN_ECONOMICS_ENGLISH

Statistical Methods in Economics

Notes Example 4: Calculate median mark from the following data:

Marks 0—20 20—40 40—60 60—80 80—100
No. of students 8 16 24 12 40

N − cf
Solution: Median= L + 2 × c
f

Marks f cf

0—20 8 8
20—40 16 24
40—60 24 48
60—80 12 60
80—100 40 100
N = 100

N
Median class = th class
2
100
= th class
2
= 50th class, i.e. 60 – 80
L= 60
N = 50
2
cf = 48
f = 12
c = 20
Substituting the values in the formula, we get
N − cf
Median = L + 2 × c
f

50 − 48
Median = 60 + × 20
12

2
Median = 60 + × 20
12
40
Median = 60 +
12
Median = 60 + 3.33
– Median mark = 63.33.

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