SAMPLE DESIGN AND SAMPLING
PROCESS
Introduction.
• Samples are parts or portions of population.
• A population is the specified total of study
elements.
• A target population, also known as the universe,
includes all the members of a real or hypothetical
set of people, event or subjects to which we wish
to generalize the result of our research.
• A study population is that aggregation of
elements from which the sample is actually
selected.
, Cont’
• Sampling means selecting a given number of subjects
from a defined population.
• The selected items together are then assumed to be
representative of that population.
• Once the researcher has clearly defined the problem
and developed an appropriate research design and
data collection instruments, the next step in the
research process is to select those elements from
which the information will be collected.
• If it were possible a researcher would collect data from
every member of the population of interest.
• Such a compete study of a population is called census.
, Cont’
• However since conducting a census is a very expensive and
time consuming exercise, a more efficient way would be to
collect information from a portion of the population.
• Such a portions of the population are known as a sample.
• A researcher may therefore study a sample and on the
basis of the information collected from the sample, make
inferences about the population.
• The ability to make this inference from a sample to a
population depends on the method by which the sample is
selected.
• Unlike sampling, if the researcher were to collect data from
each and every element of the population then the
procedure would be called a census or 100% investigation.
PROCESS
Introduction.
• Samples are parts or portions of population.
• A population is the specified total of study
elements.
• A target population, also known as the universe,
includes all the members of a real or hypothetical
set of people, event or subjects to which we wish
to generalize the result of our research.
• A study population is that aggregation of
elements from which the sample is actually
selected.
, Cont’
• Sampling means selecting a given number of subjects
from a defined population.
• The selected items together are then assumed to be
representative of that population.
• Once the researcher has clearly defined the problem
and developed an appropriate research design and
data collection instruments, the next step in the
research process is to select those elements from
which the information will be collected.
• If it were possible a researcher would collect data from
every member of the population of interest.
• Such a compete study of a population is called census.
, Cont’
• However since conducting a census is a very expensive and
time consuming exercise, a more efficient way would be to
collect information from a portion of the population.
• Such a portions of the population are known as a sample.
• A researcher may therefore study a sample and on the
basis of the information collected from the sample, make
inferences about the population.
• The ability to make this inference from a sample to a
population depends on the method by which the sample is
selected.
• Unlike sampling, if the researcher were to collect data from
each and every element of the population then the
procedure would be called a census or 100% investigation.
