Unit 4 Flashcards
What are the principles of the Selection of Participants?
Who are they?
How many are needed?
Where are they located?
How will they be selected?
What are researchers in psychology usually interested in?
drawing conclusions about some very large group of people
How do we call a very large group of people in research?
population
e.g.: American teenagers, children with autism, professional athletes, etc.
What is usually studied in the population?
only a small subset or sample of the population
What does representative mean in relation to the sample size?
sample is representative when it is a good reflection of a wider population and when the results derived from the experiment can be GENERALIZED to the population of interest
What are the three principles of participant selection?
Suitability, Accessibility, Sample Size
What does Suitability mean in the selection of participants? What does it refer to?
inclusion and exclusion criteria including any restrictions based on demographic characteristics
-> refers to how well the chosen participants match the characteristics needed to answer the research questions
What are demographic characteristics?
specific attributes of individuals that are often used to classify populations in research
-> include age, gender, race, ethnicity, occupation, marital status, geographic location
What does the sample size determine?
the number of experimental units or subjects required, based on statistical methods and specify the procedure, usually randomized, to assign subjects to the experimental conditions
What is a common critique of experiments in a study?
that a study did not have enough participants
-> difficult to generalize about population from a small sample
What is a power analysis?
calculation when designing a study, that determines the number of participants you need to recruit to detect an effect of a specific size
what is critical and essential to adequately design a study?
the sample size
What does Hypothesis Testing include?
H0 - Null hypothesis (no difference between study group)
H1 - Alternative hypothesis (There IS a difference between study groups)
Which values are ideal for a good study?
a high power value
-> elevated chance of detecting a difference between groups (confirm the H1)
What is Power value?
a percentage between 0 and 100%
-> it is a probability
What increases when sample size increases?
power
-> when too low, low probability of rejecting the null hypothesis
What is Power in sample size referred to?
Power is the probability of correctly rejecting the nullhypothesis when the null hypothesis is false
-> power reflects the likelihood of detecting a true effect in the underlying population when such an effect exists
What kind of value is excepted for a power value?
80%
What does procedure refer to in the methods section of a research paper?
to the step-by-step description of how the study was conducted
What does Accessibility Sampling Procedures refer to?
the methods and considerations involved in selecting participants for a research study
-> ensures that sample is appropriate for study goals
Which 2 types of sampling are there?
- Probability sampling
- Non-probabililty sampling
When does probability sampling occur?
when the researcher can specify the probability that each member of the population will be selected for the sample
When does non-probability sampling occur?
when the researcher cannot specify these probabilities. Most psychological research involves non-probability sampling
What is a common form of non-probability sampling?
Convenience sampling - studying individuals who happen to be nearby and willing to participate