Hypothesis
-Clear, Precise and testable statement
Should be operationalised - how you will measure …
-states what variables to be investigated
-stated at start of the study
Directional Hypothesis
-One tailed
States direction of the difference
ex. More than
Done when there is previous similar research
There is a a positive difference between IV and the DV…
Non-Directional Hypothesis
-Two tailed
States a difference between two variables
The is a difference between IV & DV
Aim
A general expression of what the researcher tends to investigate
-The PURPOSE
Independant Variable
-Manipulated by researcher to investigate the effect on The DV
Dependant Variables
- Effected by change in IV
Extraneous Variables
Participant Variables
- Features of the participant, individual differences -> e.g. a persons mood
Situational Variables
- Features of the situation, e.g. are the instructions standardised?
Confounding Variables
When SV and PV occur at the same time as IV, they become Confounding Variables
Operationalisation
- How they will be measured
Demand Characteristics
refer to any cue given by the researcher or situation, that may reveal the aim of the study & change participant’s behaviour
Investigator effects
Any effect of the investigators behaviour on the outcome of the research, the DV, or design decisions
->’Expectancy effects’ is where the investigator provides unconscious clues
Randomisation
the use of chance when designing investigations to control for the effects of bias
e.g. random allocation of participants to conditions
Standardisation
Hypothesis writing tips
Experimental Design
different ways of organisation for testing participants (RIM’ed)
Independant groups
-One group does Condition A the other does condition B
-PPTS are randomly allocated to experimental groups
+ no order effects -> tested 1, can’t practise/get tired, will not guess the aim ->behaviour more ‘natural’ -higher realism
Repeated Measures
+ participant variables, the people in both conditions have the same charachteristics
+ Fewer participants -> more economical as saves time recruiting and money spent
Matched Pair design
-2 groups of participants - related as paired on participant variables
+matched on variables relevant -> control ppt variables & enhances the validity
+no order effects -> only doing condition once -> no fatigue/practice effects
- matching isn’t perfect as time consuming
-need twice as many ppts than RM for same data -> time spent recruiting
Laboratory experiment
+EVS & CVs can be controlled -> effects are minimised -> cause & effect between IV and DV can be demonstrated -> high internal validity
-lacks generalisability -> artificial tasks & ppts may be aware that they are changing the study -> low external validity
Field Experiment
a natural setting, researcher goes to participants
-IV is manipulated & effect on DV is recorded
+more natural -> produce more authentic behaviour -> more generalisable
+ppt’s are unaware they are being studied -> no change in behaviour due to demand characteristics ->greater external validity
- more difficult to control CV/EVs -> changes in DV = CV/evs -> hard to establish cause & effect
Natural experiment
-IV is not manipulated, changes naturally -> it will change without an experimenter.
-IV varies
-DV is naturally occurring or may be devised by experimenter & measured in a field/lab
+only practical/ethical option, greater external validity ->involves real-world issues like stress & exams ->more relevant & valid
-natural event may be rare, ppt’s aren’t randomly allocated
Quasi experiment
IV based on pre-existing difference between ppl e.g. gender -> just exists
DV can be naturally occurring or devised by the experimenter and measured in field/lab
+high control, comparisons can be made between people
-ppt’s not randomly allocated, casual relationships not demonstrated