Experimentation- Sampling Flashcards
Where it is impractical to measure every individual what can be done?
A representative sample of the population is selected
In sampling what determines the appropriate sample size that should be taken?
The extent of the natural variation within a population. More variable populations require a larger sample size
What does a representative sample share with the population as a whole?
A representative sample should share the same mean and the same degree of variation about the mean as the population as a whole
What is the different types of sampling?
-Random sampling
-Systematic sampling
-Stratified sampling
What is random sampling?
Members of the population have an equal chance of being selected. It is usually used when the population being tested is very large or uniform
What is systematic sampling?
Members of the population are selected at regular intervals e.g. every 3rd person is sampled
What is stratified sampling?
The population is divided into categories that are then sampled proportionally
How are all populations show natural variation?
More variable populations will require a larger sample size. Less variable populations can be measured effectively with a small sample
What is a representative sample?
It should share the same mean as the population as a whole. It should share the same variation about the mean as the population as a whole
