Sampling 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 !