1. THE CONCEPT AND ESSENCE
OF THE SELECTIVE METHOD.
DETERMINATION OF
AVERAGE AND MARGINAL
ERRORS OF
REPRESENTATIVENESS
https://econ.biem.sumdu.edu.ua/
D E P A R T M E N T O F E C O N O M I C S ,
E N T R E P R E N E U R S H I P A N D B U S I N E S S
A D M I N I S T R A T I O N

2. SELECTIVE METHOD
An observation that characterizes
the entire set of units based on the
study of its part is called selective.
The main tasks of selective observation:
Studying the average size of the
investigated feature
Study of the specific weight (share)
of the studied characteristic in the
aggregate
method of selecting units
The accuracy of the results of the selective
method depends on:
the degree of fluctuation of the
characteristic in the aggregate
the number of observed units

3. BASIC NOTIONS OF THE SELECTIVE METHOD
Selective population - a part of the
general population that is subject to
examination.
(letter n)
selective average - x
The general population is the total
population of units from which the
selection is made.
(letter N)
general average - x ~
-
The general and selective averages do not match. This is due to the representativeness error.
Marginal error of representativeness - or where w is the share of the studied trait
in the general population, and p is the share of the studied trait in the sample population.

4. ERRORS OF REPRESENTATIVENESS
Systematic Errors
arise as a result of
violation of the
principles of selective
observation.
Random errors of
representativeness
are caused by the fact
that the selective
population does not
accurately reflect the
average and relative
indicators of the
general population.

5. FACTORS AFFECTING
REPRESENTATIVENESS ERRORS:
indicators of variation of a certain characteristic
(e.g. dispersion): the greater the indicator of
variation, the greater the size of the error
from the method of selection (repeated or non-
repeated)
from the size of the sample: the larger the
sample, the lower the probability of error
(error size)

6. Method of selection
Repeatable Unrepeatable
When determining the
average size of the
investigated
characteristic (x)
When determining the
share of the
investigated feature
(w)
MEAN ERROR OF REPRESENTATIVENESS
n i s t h e n u m b e r o f u n i t s o f
t h e s a m p l e p o p u l a t i o n
N i s t h e n u m b e r o f u n i t s o f
t h e g e n e r a l p o p u l a t i o n
- t h e s h a r e o f u n i t s o f
t h e p o p u l a t i o n b e i n g s t u d i e d
- s h a r e o f p o p u l a t i o n
u n i t s t h a t a r e n o t
i n v e s t i g a t e d

7. THANK YOU