4.2.6 Step 6: Determine the research frame
4.2.6.1 The survey area
The research is conducted at the military hospital situated in
Libreville in Gabon.
4.2.6.2 The study unit
The study is carried out at the military hospital located in
Libreville, Gabon. The research is selected in this city because Libreville is
perceived as the capital, the largest and the most populated city of Gabon.
4.2.6.3 Population
The population refers to the broader group from which sampling
elements are taken and to which results can be summarised. The population
includes all the people which characterize the unit of evaluation. A target
population should be defined in very particular terms. This will make the
selection of respondents from the population for sampling, simpler (Terre
Blanche et al., 2006:133).
Self-administered questionnaires were distributed to all
existing patients of the military hospital in Libreville, Gabon, 18 years or
older, males and females, who had experienced medical services and stayed over
at the military hospital for at least one night. Questionnaires were only given
to them once they have been discharged from hospital.
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However, individuals who did not experience medical services
at the military hospital were excluded from the study. Figure 4.2 provides a
sum up of the target population, sample units, sample elements and actual
sample size of the study.
Figure 4.2: Target population, sample units, sample
elements and actual sample size
![](Service-quality-at-a-military-hospital4.png)
Patients of the military hospital
All patients to the military hospital in Libreville,
Gabon
Target population
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Sample unit
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Military hospital in Libreville, Gabon
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Sampling elements
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Patients experiencing services at the military
hospital
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(Period of March 2013)
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Actual sampling size
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200 patients
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Source: Researcher's own construct
The sampling technique used to choose a representative sample
for the study was crucial for the research and will be described next.
4.2.6.4 Sampling method
The sampling procedure includes any process using a small
number of constituents from the entire population to draw conclusions related
to the whole population. A sample is an extract of the broader population. The
aim of sampling is to allow researchers to assess some unknown population's
traits. There are two major sampling techniques namely probability and
non-probability sampling. Non-probability sampling is based upon the
researcher's own judgement to choose the sample where he or she chooses what
elements to incorporate. Probability sampling takes place when sampling
constituents are chosen by chance. All units may not necessarily have the same
chance
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of being chosen, but the probability of choosing each unit can
be specified. Non-probability sampling involves convenience sampling, judgement
sampling, quota sampling and snowball sampling. Probability sampling techniques
encompass simple random, systematic, stratified and cluster sampling (Rahman
& Miazee, 2010:27-28).
In this research, the probability sampling technique was used
to choose respondents in the study, since it constitutes the root for all
survey research (Parasuraman et al., 2007:340).
4.2.6.5 Probability sampling method
This sampling technique was used in this research. Probability
sampling is usually appropriate in survey-based research where one is required
to make interferences from the sample about a population to resolve research
questions. Probability sampling can be divided into four phases:
? Recognise an appropriate sampling framework based on research
objectives;
? Select a proper size of sampling;
? Choose the most suitable sampling method, choose the sample;
and
? Verify that the sample is a good representation of the
population (Holder, 2008:73).
The probability sampling technique was selected for this
research since in this technique, each unit of the population, namely all
patients 18 years or older, males and females, experiencing services at the
military hospital in Libreville, Gabon had a known, non-zero chance of being
incorporated in the sample. Sampling was not conducted at the discretion of the
researcher.
4.2.6.6 Sample technique
In this technique, the probability of each unit being chosen
from the population is known and is often equivalent to all cases. This
indicates that there is a possibility to resolve the research questions by
statistically estimating the population traits from the sample (Parasuraman et
al., 2007:340).
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There are five major methods which can be utilised throughout
probability sampling. These are (Zikmund & Babin, 2007:273):
? Simple random sampling: In this sampling method, every unit
in the population has a known and same chance of being chosen in the sample.
Each unit is chosen independently. Simple random sampling will comprise of
putting all the units of the population in a container, and extracting the
sample from this.
? Systematic sampling: In this technique, the units of the
population are counted from one to the number of units that constitute the
sample, Prior to completing systematic sampling, the population size should be
divided by the volume of the sample to establish an interval i. The response is
rounded off to the closest integer. If the population is 100 000 units and a
sample of 1 000 is chosen, then one will divide 100 000 per 1 000 which is 100,
to find the interval.
? Stratified sampling: It refers to a two-stage procedure
where the population is primarily divided into strata or subgroups. A
population stratum is a fragment inside that population which has one or more
similar features. These strata must be communally exclusive and jointly
complementary. This implies that every unit must be incorporated into only one
subgroup. In the next stage, units are chosen from every strata or subgroup
through simple random sampling.
? Cluster sampling: With this technique, the population is
divided into communally exclusive and jointly complementary clusters, after
which some clusters are chosen in the sample. Cluster sampling is opposed to
stratified sampling since a variety of clusters must be as similar as possible.
The units of all the clusters will thus have the same traits. The supposition
is thus made that any of the chosen clusters in the sample will correspond to
the clusters which are not chosen in the sample.
? Two and multistage sampling: This method is often utilised
to solve issues related to a geographically dispersed population when
face-to-face contact is required, but will be too costly. Through that method,
a sample is primarily extracted from the population, such as in the
metropolitan regions in Gabon. From it, a second sample will be made, as in
particular residential zone in a metropolitan region and finally, another
sample will be made from that to concentrate only on a particular street in the
residential zone.
Both, stratified sampling and simple random sampling were
conducted in this research. The motive for choosing that sampling method was
that the sampling framework of the research was divided into strata, and the
sampling procedure was conducted
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independently of each stratum. Stratified samples are
perceived to be very efficient, and they enable investigating the interests of
particular subgroups inside the population. Stratified random sampling provides
better representativeness of the whole population, and also leads to fewer
sampling errors, providing more accuracy in estimation (Du Plessis, 2010:140).
In stratified sampling, strata should be mutually exclusive and jointly
exhaustive in that each population element should be assigned to one and only
stratum and no element should be excluded (Malhotra, 2007:327). The Department
of Internal Medicine of the military hospital in Libreville in Gabon is divided
into four main units, each unit represented an independent stratum.
As there is only one reception in each unit, no further random
selection was required. As all the clinical units were not equal in size and
did not serve an equal number of patients, a proportionate number of patients
who received medical services for at least one night were selected at each unit
(stratum). Self-administered questionnaires were distributed to identify
patients at each unit. Permission to conduct the study was obtained from the
nurse manager of the Department of Internal Medicine of the military hospital
in Libreville in Gabon. The patients interviewed at each clinical unit were
randomly selected. The study made use of a simple random technique where each
population element had not only a known, but an equal chance of being selected
(Munyaradzi, 2010:209). If a patient did not want to be involved in the
research, the next willing patient was selected, and thereafter, the second
patient after each willing one.
4.2.6.7 Sample size
The volume of the sample implies the statistical accuracy of
the findings. The size of the sample is a result of alteration in the
population parameters and the assumption of quality which is needed by the
researcher. In general, bigger samples reduce the likely error in generalising
the population. In other words, larger samples are more representative of the
population and result in more accurate findings. The volume of the sample can
also be decided on the basis of personal judgement and statistical evaluations
(Terre Blanche et al., 2006:236).
In the Gabonese health care industry, though some hospitals
keep records of their patients, this is expected to be a problem for some
medical institutions. The core reason is the durability of the service product
sought by patients from hospitals from time to
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time. It is difficult to tell when a patient will re-visit and
purchase the service at the hospital. Against this background, the following
formula will be used to estimate the response rate and the actual sample size
needed (Saunders et al., 2007:214):
na = (n x 100) / re
%
With:
na= is the current sample size
needed
n = is the minimum (or
adjusted minimum) sample size
re % = is the estimated
response rate expressed as a percentage
This calculation is based on three major aspects namely the
level of confidence of the accuracy of the estimate, the margin of error which
can be accepted, and the proportion of answers that the researcher expects to
have some particular attribute.
Assuming that the researcher knows the level of confidence and
the margin of error, it will be easier to have an estimation of the proportion
of answers that the researcher expects to receive some particular attribute
(Saunders et al., 2007). In general, researchers use a 95% level of confidence,
which means that if one selects a sample 100 times, at least 95 of these
samples will reflect the true characteristics of the population. The margin of
error relates to the precision of the researcher's estimates of the population.
The standard deviation, also known as error margin usually used in business and
management researches is 5% (Munyaradzi, 2010:211). This means that if 40% of
the researcher's sample lies in a certain category, then the estimate for the
total population within this same category will be 40% plus or minus 5%. For
the purpose of the current study, a 5% margin of error and a 95% confidence
level will be used.
Table 4.2 shows the minimum sample sizes for different sizes
of the population at a 95% confidence level to provide a good decision model
(Saunders et al., 2007:212).
Table 4.2: Minimum sample size estimates
Population
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Five per cent (margin of error)
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100
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44
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200
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132
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300
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168
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400
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196
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500
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217
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Source: Adapted from Munyaradzi (2010:212)
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Thus, according to this study, a minimum population frame of 100
patients for the military hospital in Libreville, in Gabon was estimated. This
entails that referring to the Table 4.2, the minimum sample which can be
expected is 44 respondents.
According to Saunders et al. (2007:215), a 50% response rate was
suitable for surveys done through questionnaires. Thus, since the current study
uses a questionnaire instrument to gather data, the researcher estimated a 50%
response rate.
According to the formula provided above, the expected sample size
for this research will be:
na = (n x 100) ! re % na
= 100 x 100 ! 50 na = 200
This entails that the sample size for this study was 200
respondents.
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