THE SIMPLE RANDOM SAMPLE
01/27/08
DEFINITION.
Statistical inference
is a procedure by which we reach a conclusion
about a population on the basis of the information contained in a
sample
that has
been drawn from that population
. [A sample is a
subset
, or
part
of a population.]
There are many kinds of samples that may be drawn from a population, but only
scientific samples
can be used for making
valid
inferences about a population. The
simplest of them is the
simple random sample
.
DEFINITION.
If a sample of size
n
is drawn from a population of size
N
(N > n) in
such a way that every element in the population has an
equal chance
of being chosen as a
part of the sample,
then such a sample is called
a simple random sample
.
Correspondingly,
every
possible sample of size
n
has the
same chance
of being selected.
[A size of a population (or a sample) is the number of entities in it.]
{In general, a procedure used to collect the sample data is called
sampling plan
or
sample design
.}
The mechanics of drawing a sample
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 Spring '05
 Kzaer
 Simple random sample

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