Eui-chan Lee
How is sampling related to the scientific
experiment?

Purpose of the scientific research is to describe,
predict, and explain a potential relationship
between at least two variables

Most importantly to generalize the information
and gain knowledge that allows us to have a
better understanding of ourselves and the world.
How is sampling related to the scientific
experiment?

However, the target population could be too large
to be tested all at once.

So, we select people who represent the target
population and do the experiment on them instead
of dealing with the whole population
Definition of sample:

Subset of all cases of all the population
that we choose to study
Important thing to remember about
sampling….

Although sampling is used to give us a beneficial
information, we could be led to a false information
if the sample is not a good representative of the
population
1. Sample size
2. Sampling technique
1. Sample size:

As the sample is what represents the target
population, the bigger the sample size, the lesser
the likelihood of sampling error
Better!
1. Sample size:

If the sample size is too small relative to the
population, there will be a big sampling error
For example…
“The college students in the U.S who sleep
6 hours a day live longer than those who
sleep 4 hours a day on average during
each semester.” (N = 5)
There is a big chance that the result will be
significantly different every single time we
conduct the experiment due to its small
sample size
No consistency → No generalization of the info.
2. Sampling techniques

“Random sampling” in which each member of the
population is equally likely to be chosen as a part of
the sample.

If the selection is not made through the random
selection, there is a possibility that the characteristic
of the sample would falsely represent the
characteristic of the population
For example…
“On average, people read three books every month”
It might not be a proper conclusion to make if
your data is collected only from some scholars
at a higher Institution
Middle school students / uneducated people
might show different tendency
Summery

To draw any reliable and valid conclusions
concerning the population, it is imperative that
the sample be “LIKE” the population in terms
of its size & characteristics

How can we protect ourselves from all the false
information that comes from biased sampling
method?
BE
SKEPTICAL !