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of freedom at a given confidence level. This is

derived from table value.

e = Margin of error

P = Population proportion (it is 50% usually 0.5)

N = Population Size

n = Sample size

Illustration 2.2.1: Calculate sample size if population size (N) is
30000.

Solution:

The confidence level is taken as 95 percent with degree of
freedom 1, then the (χ ) Chi-Square value will be 3.841(taken
2
from table value).

Margin of Error (e) at 95percent confidence level is 0.05

Population Proportion (P) is 50 percent = 0.5

When we substitute the values in the equation,

n =

n =

n =

n =

Therefore,
n = 379.25 that means 379 samples have to be taken to represent
a population of 30000.

b. Sample size determination for infinite population

A pilot study has to be conducted and the values have to be
used. To determine the sample size of an infinite population,
standard deviation has to be calculated for the main variables and
the highest one has to be taken to substitute in the formula (Aday
and Cornelius, 2006).

SGOU - SLM - MCom Research Methodology 73