Includes solved practical problems step by step in individual, discrete and continuous series.

1. GEOMETRIC MEAN
1. Discrete Series
X 8 10 52 25 37
f 5 3 4 2 1
x f Log x f log x
80 0 5 0.9031 4.5155
10 0 3 1.0000 3.0000
52 0 4 1.7160 6.8640
25 0 2 1.3979 2.7958
37 0 1 1.5682 1.5682
N=15 ∑f log x= 18.7435
G= Antilog {∑f log x}
N
= Antilog {18.7435}
15
= Antilog [1.249] 1+1=2
=17.74
2. Continuous series
X 4-8 8-12 12-16 16-20 20-24 24-28 28-32 32-36
f 6 10 18 30 15 12 10 6
x f m Log m f log m
4-8 12/2 6 60 0 0.7782 4.6692
8-12 20/2 10 10 0 1.0000 10.0000
12-16 28/2 18 14 0 1.1461 20.6892
16-20 30 18 0 1.2553 37.6590
20-24 15 22 0 1.3424 20.1360
24-28 12 26 1.4150 16.9800
28-32 10 30 1.4771 14.7710
32-36 6 34 1.5315 9.1890
N= 107 ∑ f log x= 134.034

2. G= Antilog {∑ f log x}
N
= AL {134.034}
107
=AL[1.2527] 1786+3=17.89 1+1=2
= 17.89
Do it yourself
1.
X 260 120 180 230 220 200
f 7 12 15 11 8 7
2.2571
188.4
2.
C.I. 10-20 20-30 30-40 40-50 50-60
f 5 10 15 7 4
E-notes by
Asst. Prof. Harpreet Kaur
Sri Guru Granth Sahib World University,
Fatehgarh Sahib