Session 5 Flashcards
What is a ‘population’?
the large group of ALL possible scores that would be obtained IF the behavior of every individual of interest in a particular situation could be measured
What is a ‘sample’?
A relatively small subset of a population that is selected to represent or stand in for the population; a subset of the complete group of scores found in any particular situation
The __________________ is everybody you are interested in learning about.
population
What is a census?
gives an accurate demographic of a population
A _____________ is subset of population and stand for and represents the population of interest.
sample
What is the link between sample and population?
Inference
What is inference?
researchers infer that the characteristics of the sample probably are the characteristics of the population
Inferences must have ______________ ____________, setting limits on the possibility that we are wrong. 1% or 5%
statistical significance
What are the two questions researchers ask when evaluating a sample?
- Is the size adequate?
2. Is the sample biased?
What makes a sample unbiased?
random samples in which every member of the population of interest have an equal and independent chance of being included int he sample
What is another name for random sample?
simple random sample
What is the biggest task of sampling?
defining the population as specifically as possible
What is a bias free sample called?
Simple random sample
Can a bias free sample contain error?
yes, but it is still bias free
What is potentially biased but easier way to approach sampling?
volunteerism
Describe two ways of volunteerism recruitment?
- researchers issue a call for volunteers
2. researchers identify a random sample from a population, but only certain people choose to participate
Why is volunteerism a source of bias?
because those who volunteer may be fundamentally different from non-volunteers
What are the two types of errors that random samples are subject to?
- Sampling Error
2. Systematic Error
What is sampling error?
the difference, due to random choice, between a sample statistic and the population parameter it represents
What is Systematic error?
the difference, due to non chance errors, between a sample statistic and the population parameter it represents
Is a sample EVER perfect?
- there will never be a perfect representation of population.
- there will always be sampling error
Sampling error is created by_______ ___________.
random chance
Sampling Error is reduced by ___________________.
adequate sample size
Sampling error is evaluated with ________________.
inferential statistics
Systematic Error is created by ______________.
bias in sampling
Systematic error is reduced by _______________.
using sampling methods that are less subject to bias