research methods Flashcards
Independant variable
In an experiment, it is the variable that it controlled and manipulated by the researcher.
Dependent variable
The variable that is measured by the researcher as a result of the manipulation to the IV.
Extraneous variables
These are generally unwanted variables that can have an impact on the relationship between the IV and the DV.
There are two types of extraneous variable: participant variables and situational variables
Participant variables
These relate to individual characteristics of a participant that may impact how they respond
Situational variables
These relate to things in the environment that may impact how each participant responds.
What are the 3 ways to reduce extraneous variables?
1) Standardisation
2) Random allocation
3) Double blind procedure
Standardisation
Keeping parts of the procedure the same so each participant experiences the same procedure.
Random allocation
Participants are randomly allocated to conditions rather than an experimenter choosing.
Double blind procedure
Neither the participants taking the test nor the experimenter know which condition the participants are in.
What are the 4 sampling techniques?
Random sampling
Stratified sampling
Volunteer sampling
Opportunity sampling
Random sampling technique
Every member of a population has an equal chance of being selected.
Strengths of random sampling technique
- It provides the best chance of an unbiased representative sample.
- Data more likely to be considered generalisable.
Weaknesses of random sampling technique
- It is time consuming
- A representative sample is not guaranteed; some participants may refuse to participate leading to a less representative sample.
Stratified sampling technique
A technique that ensures subgroups of a target population are proportionately represented in the sample.
Strengths of stratified sampling technique
- Ensures that the sample is completely representative as a cross-section of a target population.
-Useful if a small subgroup of the target population may be missed.
Weaknesses of stratified sampling technique
- It can be time consuming
- People can still refuse to take part
Opportunity sampling
Simply selecting those people that are available at the time.
Strengths of opportunity sampling technique
- Quick and convenient
- Saves time and effort
Weaknesses of opportunity sampling technique
- Can lead to biased sample since not every member of the target population will be around at the time of the study.
Define experimental designs
Experimental designs is how the participants are split into conditions.
Name the 3 types of experimental designs
1) Independent groups design
2) Repeated measures design
3) Matched pairs design
Independent groups design
Participants are split into conditions with each group tested in only one condition of the study.
Strengths of independent groups design
- It removes order effects as participants only complete one condition so the results are more valid
Weaknesses of independent groups design
- There may be individual differences between groups which can reduce the validity of the results.
- More participants are needed which can be time consuming to collect and test.
Repeated measures design
The same participants are used in all conditions.
Strengths of repeated measures design
- It compares the same participants so the changes are real which makes the results more valid.
- You don’t need as many participants which is less time consuming and makes them quicker to collect.
Weaknesses of repeated measures design
- Possibility of order effects. Participants’ performance is determined by the order that they complete the conditions. This reduces the validity of the results.
- Demand characteristics more likely as participants are more able to guess the aim.
Matched pairs design
Different participants in different conditions who are matched on a characteristic.
Strengths of matched pairs design
- It controls for individual differences which increases the validity of the results.
- Fair comparisons can be made between the groups as they are equally matched.
Weaknesses of matched pairs design
- It can be difficult and time consuming to match all participants.
Hypothesis
A hypothesis is a precise, testable statement of what the researchers predict will be the outcome of the study.
What are the two main ways of expressing a hypothesis?
1) Null hypothesis
2) Alternative hypothesis (experimental hypothesis)
Null hypothesis
States that there is no relationship between the two variables being studied, so the IV does not affect the DV.
Any results found are due to chance.
Alternative hypothesis
Also called an experimental hypothesis when the method of investigation is an experiment.
States that there is a relationship between the two variables being studied, so one variable will have an effect on the other.
What is the difference between a directional and non-directional hypothesis.
Directional hypothesis: A hypothesis that predicts the direction the results will go in.
Non-directional hypothesis: A hypothesis that predicts a difference/relationship will be found, but doesn’t specify what that difference/relationship will be.
What are the three types of experiments
1) Lab experiment
2) Field experiment
3) Natural experiment
Laboratory experiment
These normally take place in a controlled environment, such as a lab.
The researcher deliberately manipulates the IV while maintaining strict control over the extraneous variables through standardised procedures.
Strengths of laboratory experiments
- Strict controls and procedures mean other researchers can easily replicate lab experiments and check for reliability.
- High control over extraneous variables implies cause and effect can be studied without any influence from other unwanted variables, which helps with internal validity.
Weaknesses of laboratory experiments
- The artificial setting means participants might not demonstrate real-life behaviour, dramatically reducing ecological validity.
- Participants are invited to the experiment so they may display demand characteristics.
Field experiments
An experiment conducted in a natural environment, but there is still an IV that is manipulated by the researcher and a DV that is measured.