Variables Flashcards
(12 cards)
What is an independent variable?
The variable that is deliberately, manipulated or varied by the experimenter.
What is a dependent variable?
The variable is the variable that is measured in order to understand the effect of the independent variable.
What is the operationalisation of a variable?
Operationalisation of a variable is the method of taking a variable and stating it in the way it is measured.
E.g. “… was operationalised as age in total months”
What is a hypothesis/what must it include?
A hypothesis clearly states how the IV will affect the DV and the population from which conclusions are drawn.
E.g. “For adult drivers in Melbourne, an increase in blood alcohol levels will cause a decrease in reaction speeds.”
What is an extraneous variable?
An unwanted variable other than the IV that could cause changes to the DV. They are usually expected and removed by the experimenter in the experimental design and are then called controlled variables.
What is a confounding variable?
A variable that acts as a second, unwanted IV, having a systematic effect on the DV.
If a confounding variable exists, conclusions cannot be accurately drawn.
What are individual participant differences?
Caused by…, Examples, Solved by…
Caused by:
> Variables that are different from one another
Examples:
> Age, gender, intelligence, personality, memory, mood, self-esteem, problem solving ability
Solved by:
> Use of the repeated measures experimental design
What are non-standardised instructions and procedures?
Caused by…, Examples, Solved by…
Caused by:
> Instructions to participants aren’t uniform which affects the participant’s responses
Examples:
> Using different descriptive words or leaving out important information when explaining procedures to participants
Solved by:
> Use of standardised instructions
What is the order effect?
Caused by…, Examples, Solved by…
Caused by:
> Subjects experiencing fatigue/boredom when performing the second condition after already performing a task
Examples:
> Participants who are in both the control and experimental groups one after another experience boredom and all perform slightly worse in the experimental condition
Solved by:
> Counterbalancing: group 1 does experiment in order AB, group 2 does experiment in order BA, IF using the repeated measures design or using a matched participant design
What is the placebo effect?
Caused by…, Examples, Solved by…
Caused by:
> Participant’s behaviour being influenced by their expectations of how they should behave
Examples:
> When being told they’re being given an antidepressant, participants expect their symptoms to be alleviated.
Solved by:
> By using a placebo (fake treatment) or by participants being unaware of what condition they’re in → (being told they’re in group A/B, but not whether they’re in the control or experimental group) → single blind procedure
What is the experimenter effect?
Caused by…, Examples, Solved by…
Caused by:
> Experimenter unintentionally influences the behaviour of the participants, therefore influencing the outcome.
Examples:
> Self-fulfilling prophecy: participants behave in a way that they believe the experimenter wants them to behave
> Experimenter bias: unintentional actions that may occur in the collection/treatment of data
Solved by:
> Use of a double-blind procedure where both the experimenter and the participants are unaware of who is in which condition (which controls for both experimenter effects and placebo effects)
What is unrepresentative or biased sample?
Caused by…, Examples, Solved by…
Caused by:
> When the sample tested on doesn’t properly represent the population, preventing the findings from being generalised.
Examples:
> When convenience sampling is used, the sample doesn’t properly represent all of the population, preventing the results from being generalised.
Solved by:
> Use of different sampling methods, like random sampling or stratified sampling.
