Task 5 Flashcards
What is a sample?
A small subgroup chosen from the larger population
What is a sub population?
Because you cannot study eighth graders from everywhere in the world, due to the monetary costs of a study, a “sub population” would be eighth graders from a certain region of the country (city,town or district).
What is the goal of research regarding sampling?
That it results based on a sample of individuals can be applied to the larger population from which the individuals are drawn.
What is generalization?
The ability to apply findings from a sample to a a larger population.
What is external validity?
Something studies possess when their findings can be applied across a variety of research settings and subject populations.
What is the best procedure to draw a sample from a population?
To use a random sample
What is a random sample?
Every person from the population has an equal chance to be selected for the study.(which allows for higher level of generality from research to real life)
What about non random samples?
-They’re used by most psychological research usually from individuals from a highly specialized sub population; like college students (meaning less external validity as you sacrifice the generality of your results)
Does sampling always have to be random?
- most research in psychology doesn’t have specific-to-specific application
- goal of most psychological research is To predict from general levels(theory) to specific (specific Behaviour)
- findings from psychological research are applied indirectly through theory and models
What factors should you consider when acquiring human participants for research?
- The setting in which your research will take place
- Any special needs of your particular research
Screen potential participants for certain characteristics(gender age etc)
-Any institutional,departmental, and ethical policies and guidelines governing the use of participants in research
Comply with the APA Guidelines
Acquiring human participants for research: Factors to consider : What are the two settings where your research could take place?
Laboratory research
Field research
What does laboratory research consist of?
Soliciting volunteers or using a subject pool (required to participate in a certain number of studies, like here in Maastricht)
What does field research consist of?
Selecting participants while they are in their natural environment (selecting participant from a population, contacting a person having them fill a questionnaire)
What is the volunteer bias?
Samples that are made up only by volunteers affect external validity
What are the factors that affect the decision to volunteer?
- the personal characteristics of volunteers (shared)
- situational factors
What are some situational factors that might increase the want for volunteering?
- Incentives to participate
- Personal characteristics of recruiter
- Amount of stress present in experiment
- The degree to which participants feel volunteering is normative
How does volunteerism relate to internal validity?
Volunteerism affects “inferred causality” which restes to internal validity
What is internal validity?
Refers to the confidence we place in the cause and effect relationship in research.
What does it mean that there is high internal validity?
We are better able to argue that the relationship is causal, whereas in studies with low internal validity causality cannot beinferred at all.
How is volunteerism related to external validity?
Volunteerism may affect our ability to generalize, thus reducing external validity
Some remedies for volunteerism?
Fck you man
What are three sampling related issues to consider when making samples from a population?
- Representativeness
- Sample technique
- Sample Size
What is a representative sample?
One that closely matches the characteristics of the population
How is a non representative sample called?
Biased sample
Representativeness: What are some ways to reduce the biased sample?
- Make an effort to determine whether it includes members from all segments of that population in which you have an interest
- to overcome biased sample lists use multiple lists
Sampling technique: Types of sampling : What is simple random sampling?
-Randomly select a certain number of individuals from the population
How is simple random sampling carried?
— statistical tests are conducted to ensure that chosen participants have really been chosen at random
— Closing your eyes and ripping your finger at random number table
—- a variant of random sampling; random digit dialing (when conducting telephone survey)
—-Select a larger sample; more likely to represent all segments of a population
What is the systematic bias?
Bias resulting from the system, leading in average to systematic errors(measured values systematically too high or low), in contrast to random errors, which in contrast cancel each other out.
What are the different types of sampling?
Simple random sampling
Stratified sampling
Proportionate sampling
Systematic sampling
Cluster sampling
Multistage sampling
Sampling technique: stratified sampling what does it consist?and what does it ensure?
- Dividing population into segments(strata)
- Degree of representativeness, but may lead to segment of population being over represented
How do you perform stratified sampling?
- Divide population into segments
2. Selecting separate random sample of equal size from each stratum
Sampling technique: What is proportionate sampling?
A variant of stratified sampling where proportions of people in the population are reflected in the sample
Sampling technique: What is systematic sampling?
It is used in conjuctiin with stratified sampling.
It consists on sampling every kth element after a random start(e.g every fourth person in a phone book)
Sampling technique: What is cluster sampling? Why is it necessary?
— cluster sampling differs because the basic sampling unit is a group of participants(cluster) rather than the individual participant.
—-it is necessary because populations can be too large to allow cost-effective random sampling or even systematic sampling.
How do you perform cluster sampling?
- Identifying naturally occurring groups of participants (clusters)
- Randomly select certain clusters
- Survey all participants within the clusters
Limitations of cluster sampling?
Limits sample to those participants found in the chosen clusters , can leave out important elements of population
Sampling techniques: What is multistage sampling?
— variant of cluster sampling
How do you perform multistage sampling?
1You begin by identifying large clusters and randomly selecting from amongs them(line cluster sampling tho specifically large)
—2.randomly select individual elements rather than selecting all elements in the cluster
When is random sampling used?
Especially to make predictions about specific behaviors.
Non random sample is perfectly fine for most research in psychology.thiugh it should include a discussion of possible limitations
Sampling size:Whatbis an economic sample?
A sample that includes enough participants to ensure a valid survey and no more
What are two factors to take into account when considering sample size?
Amount of acceptable error
Expected magnitude of differences
Amount of acceptable error: what is a sampling error?
Deviation of sample characteristics from this if the population
What does a small or larger margin of error mean?
Small—> Plan to apply results to implement changes in Behaviour
Larger—> Interested in simply deceiving a set of characteristics
What is a good way to determine acceptable margin error?
Looking at literature describing similar surveys to see what margin of error was used
Sample size: what is the expected magnitude of differences?
Idk
Once you have the acceptable error and expected magnitude of differences you can calculate sample size needed with what equation?
In waiting
What is internal validity?
The ability of your research design to adequately test your hypothesis .
How does an experiment show international validity?
Showing that variation in the i.v and only the I.v caused the variation in the d.v
How does a correlational study show internal validity?
Showing that changes in the value of your criterion variable relate solely to changes in the value of your predictor variable and not changes in other extraneous variables that may have varied along with your predictor variable
What is the rival hypothesis?
Internal validity is threatened to the extent that extraneous variables can provide alternative explanations for the findings of a study.
What is confounding?
When two or more variables combine in such a way that their effects cannot be separated
How does confounding affect internal validity?
— it doesn’t necessarily present a serious threat to internal validity.Less problematic when the confounding variable is known to have little or non effect on the dependent or criterion variable.
Why is confounding more likely to be a problem in correlational designs than experimental designs?
Because of the tight control over extraneous variables is lacking
How many sources of confounding are there?
7(gibback before exam)
When should you be concerned with internal validity
During the design phase of the study
Discovering problems with internal validity after running a study is too late and issues cannot be fixed
What is external validity ?
The degree to which the results of a study can be extended (generalized) beyond the limited research setting and sample in which they were obtained.
What is research designed in a laboratory supposed to determine?
- Whether smthg can happen, rather than whether it does happen
- Whether smthg we specify ought to happen under specific conditions in the lab does happen under this conditions
- What happens under conditions not encountered in the real world
When does external validity matter?
When it is aimed at developing a better understanding of underlying mechanisms of Behaviour (basic research) than applied research
What are factors that affect external validity?
Reactive testing
Interactions between participant selection biases and the independent variable
Reactive effects of experimental arrangements
Multiple treatment inference
Where can you better control the internal validity?
In laboratory research
Where can you better control external validity?
In field research
What is the laboratory setting?
Any research setting that is an artificial relative to the setting in which the Behaviour naturally occurs.
What does laboratory setting give you?
A bigger control over the variables that could affect your results ñ.
What should you do when you want both external validity(generalize your results) and internal validity?(control extraneous variables)
You could use a simulation
What is a simulation?
An attempt to re create as closely as possible a real world situation in the laboratory
Why should you simulate?
— because you can simulate Behaviour that is not ethical to study in the real world
—it is more practical less expensive
What happens when you make a simulation more realistic?
The more chances you have that the results are aplicable to real-world phenomena
Remember that it isn’t always necessary for the physical reality to be highly realistic.E.g jury simulation studies do not re-create physical setting of a court room
What are the two types of realism?
Mundane realism
Experimental realism
What is mundane realism?
Degree to which a simulation mirrors the real world event
What is experimental realism?
Degree to which the simulation involves the participants in the experiment
What is the field setting?
Research setting in which the Behaviour under study naturally occurs
What kind of methods does a field research employ?
Non-experimental (correlational methods such as naturalistic or survey designs )
What is the field experiment?
Is a laboratory experiment meaning that you manipulate the variables (I.v) etc butnis conducted in the real world rather than in an artificial setting
Advantages and disadvantages of field experiment
—Advantage: results can be easily generalized to the real world
—Disadvantage: Little control over potential confounding variables
