
Chapter 3
PB
Measures of Central Tendency
101
TABLE 3.25
Computation of median for Example 3.15
Vacations availed Number of employees (f) Cumulative frequency (cf)
0–10 2 2
10–20 18 20
20–30 30 50
30–40 45 95
40–50 35 130
50–60 20 150
60–70 6 156
70-80 3 159
Sum
fN
i
==
∑
159
Here, N = 159, which is an odd number.
N
=
159
79 5=
which falls in the class 30–40 (see the row of the cumulative frequency 95
which contains 79.5). Hence, the median class is 30–40.
l = lower limit of median class = 30
f = frequency of median class = 45
c = total of all frequencies preceding median class = 50
i = width of class interval of median class = 10
Median = l
N
c
f
i+
⎛
⎝
⎜
⎞
⎠
⎟
−
×
2