REVIEW OF THE LITERATURE
CHAPTER 4 RESEARCH METHODOLOGY
4.7. Sample Surveys of Supply Chain Partners
4.7.5. Link 6: Final Consumers Population
The population to be sampled consisted of consumers aged 18 and over in Northern Greece. The question immediately arose whether remote areas -such as Florina and Kastoria (in the West) and Alexandroupoli and Komotini (in the East)- should be included. Interviewing in such areas is time-consuming and the cost tends to be disproportionately high, compared to the value of the results.
For all these reasons, the city of Thessaloniki was selected as the main area of investigation since it combines the following elements:
a) It is the second biggest city in Greece and the biggest city of Northern Greece.
b) It brings together people coming from smaller cities/towns or villages of Greece thus people with different cultural backgrounds.
c) Its residents comprise of people coming from different economic backgrounds.
The sampling of the Final Consumers, was totally random. The investigation time was divided into three Saturday mornings. In each one, three different interviewers20 were based in two different big grocery markets. In total, the interviewers visited 18 different places. The investigation was not focused in a specific area of the city of Thessaloniki, but instead the following areas were visited:
Kalamaria, Depot, Center, Ksirokrini, Evosmos, Stavroupoli, Neapoli, Polichni, Kordelio, Menemeni, Meteora, Efkarpia, Retziki, Panorama, Pylaia, Toumpa and Charilaou, covering in this way most areas of the city. This spread was necessary, in order to ensure the full participation of people, coming from different economic levels.
The main duties of the two research assistants was to approach the final consumers and persuade them to participate in the research. Although the
20 Georgakoudis Elias, Dr. Michaleas Antonios, Tsemekidis Konstantinos
Chapter 4 – Research Methodology
142 researcher had previously provided the assistants with information on how to answer specific questions that might come from the final consumers, the assistants fed back no problems or misunderstandings by the consumers. The contribution of the two assistants to the research proved to be significant since it saved time for the researcher, speeding up the whole process.
Figure 4.6. City of Thessaloniki: Areas where the investigation was carried out
Sample Size
Undoubtedly, price is a very important factor in buying a product although it is not the most important factor for all the consumers and in every buying decision. The type of the product itself influences the relevance of the price with the final buying decision of the consumer. According to the Farmers Guardian, a survey carried out by BBC’s Countryfile programme (In Brief, 2012), showed that 92% of the respondents felt price as the most important factor when buying food.
On the other hand, according to Bohen (2007) price was the main factor in buying technology products for only 23% of the respondents, followed by quality (21%), brand (11%), recommendations from sales associates (15%) etc.
Based on the Greek experience, price is very important when it comes to every day products. According to a survey carried out in Greece in 2009 by the General Secretariat for Consumers (2009), nearly seventy percent of the consumers underline price as one of the most important factors in which they base their buying decisions. Nowadays, this fact is further strengthened by the difficult economic conditions occurring in the country, influencing the life of the Greek citizens.
143 For all the previous reasons, the size of the sample was determined based on the assumption that the most common factor affecting the buying decisions of the consumers is price. It was expected that a very high percentage of the respondents (80%) would think of price as the most important factor in buying a product.
So, in order to estimate the proportion of π in the population who think of price as the most important factor in their buying decisions, the standard error of the estimator is:
. . = 1 −
1 −
Then
. . = 1 −
And inverting this formula, we obtain:
= 1 −
[. . ]
So, it is expected that (π) 80% of the consumers would think of price, as the most important factor in buying a product21 and a standard error of more than 2,5%
would be undesirable, then the required sample size is n=256 (Moser and Kalton, 1971).
=0,81 − 0,8
0,025 = 0,16
0,000625= 256
Because of the fact that the sample size is small in comparison with the population size N (the sample of 256 people, represents the 0,0213% of the approximately 1.200.000 population of Thessaloniki), there is no need to use a finite population correction factor (fpc). The f.p.c. factor is used to define both the standard error of the mean and the standard error of the proportion when the sample size is big in comparison with the population size N and the finite population correction factor would not be negligible. In this case, the following equation would reduce the initial estimate to the most appropriate sample size, that would have given the required degree of precision.
′= 1 +
21 Further details on the specific issue can be found in Chapter 5.7.3 – Summary of the Questionnaires: Final Consumers (FC).
Chapter 4 – Research Methodology
144 The sample was selected randomly, in order to ensure the validity of the data.
The sample consists of 271 people, giving a slightly smaller standard error of 2,4%:
= 1 −
[. . ]=> 271 =0,81 − 0,8
[. . ] => [. . ]=0,16 271=>
[. . ] = 0,000590 => [. . ] = 0,024
Of the respondents, 148 (54,6%) were female and 123 (45,4%) were male.
The predominance of the women in the sample was expected because of the day and the places where the investigation was carried out.