Research Methods Flashcards
Independent Variable (IV)
- the variable directly manipulated by the researcher in order to examine its effects
- may have 2 or more levels ( ex: different concentrations of IV)
- they are the “conditions being tested in the experiment”
Dependent Variable (DV)
- the variable being measured by the researcher in a study
- is affected by the manipulation of the IV
- outcome of the study
Operationalisation
-making the variables in an investigation detailed and specific
Note:
It is important that both the IV and DV are operationalised so that they are testable and measurable
-We make variables detailed and specific so that another research can know what is measured, changed and how
Extraneous Variables
- factors in an investigation that may interfere with the IV or DV and affect the findings of the study
- situational variables and participant variables
- variable that is not controlled
- need to be controlled to prevent them from affecting the outcome of the study
Confounding Variable
- an extraneous variable that is not controlled and so has an affect on the outcome of the study
- results in the effect of the IV not being truly seen
- it confounds(damages) the results
Situational Variables
-an extraneous variable present in the environment of the study
Ex:
Noise, distractions,light levels and temperature
- How the study was conducted can introduce situational variables
- can influence the study if they vary between conditions
Ex: one group of participants participate in a written task in poor light vs the groups of participants who performs the same task in good lighting
Order effects (under situational variables)
When participants improve or worsen in the second condition because they have practised or become fatigued
If a study requires participants to repeat a test, two possible implications may arise:
Participants have improved
-they became used to the test, repetition( active recall) often results in higher score
Participants have worsened
-they became tired or bored
so they do less well
Demand characteristics (under situational variables)
-when the participants alter their behaviour to meet the perceived aims of the study
Investigator effects
- can also encourage demand characteristics
- when a researcher unintentionally gives clues to the participants about how to behave, altering their behavior
Ex: investigator nodding his head, when the participant does the right thing
Participant Variables
-extraneous variables specific to participants in an investigation, for example, their mood, ability, personality type, upbringing
-participants bring with them various traits and tendencies that could influence the outcomes of the results
esp if a certain type of participant ( ex: a psychotic, aggressive participant )is present in one condition of the
study and not the other
- the researcher only needs to consider what participant variables may influence the results of their study
ex: driving ability is highly unlikely to affect a short-term memory experiment
What to do about Extraneous Variables?
Researchers either eliminate or control them
Eliminating variables= removing the likelihood of them occurring ex: putting a “silence” sign outside ex
Most extraneous variables are difficult to eliminate but they can be controlled
Controlling Situational Variables
Ways to control situational variables
- Standardised Procedure
- To combat the order effect
- counter balancing
- randomisation - To control demand characteristics
- single-blind technique
- double-blind technique
Standardised procedure
-keeping the situation and procedure of a study exactly the same across all conditions of an investigation
example:
if the noise is at a certain level for one condition of the experiment, it should be exactly the same for the other conditions of the study
counterbalancing
a technique used to combat order effects/eliminate the impact of order effects
- “Where half of the participant group experiences condition A then condition B, while the other half experiences condition B then condition A”
- This way the order effects of either improvement or decline in performance are equally distributed in both conditions to cancel each other out
randomisation
-another technique used to combat order effects
- based on the same principle as counterbalancing but this is an investigation
“ where participants are randomly assigned to condition A or B as their first or second test condition”
single-blind technique
- can be used to control demand characteristics
- when the information and aims of the study are withheld from the participants
double-blind technique
- used to control demand characteristics encouraged by investigator effects
- when the information and aims of the study are withheld from both the participants and the researchers
Controlling participant variables
Ways to control participant variables
- Use same participants in both conditions of the study
- so data for each participant compares across all conditions - Use different participants but make sure they are matched on important characteristics
- Random allocation
Random allocation
- can also be used to control participant variables
- “when participants are randomly assigned to one condition of the study or the other” basically random distribution
- not fool proof but its is designed to prevent only a certain type of person being in one condition of the study
Hypothesis
- statement of the predicted outcome
- the way in which a hypothesis is written depends on whether:
1. it is looking for a difference between conditions (as a result of the iv)
2. it is looking for a relationship between variables (in a correlation)/trend
Null hypothesis
-“a prediction that the results will fail to show any difference (or relationship) that is consistent or systematic”
Ex:
for difference between conditions( result of IV)
-There will be no difference in the number of digits recalled whether the participants listened to classical music or jazz; any difference will be due to chance
for relationship between variables (correlation)
-there will be no relationship between the amount of time spent revising and percentage score on the test; any relationship found will be due to chance
Why we add “any difference or relationship will be due to chance”
-because it is highly unlikely that no difference will be found (due to participant variables) , there may be a very small difference (ex: 0.9%) but the difference found will be too small to be due to the manipulation of the IV
Alternative (experimental) hypothesis
- “A prediction of the expected outcome of a study, usually based on a theory”
- can be either a “directional hypothesis” or “non-directional hypothesis”
Directional hypothesis
- “a hypothesis that predicts the direction the results will go in”
- if a theory makes a clear claim, a directional hypothesis can be used ( because the theory already claims what expected direction the results will go in)
ex:
- Adults will recall more digits than children (difference in conditions)
- There will be a negative correlation between self-esteem and depression (relationship/correlation)