exam prep.
,PYC3704 – Psychological Research
Topic 1
Inferential Statistics – concerned with inferring numerical properties of statistical populations from
sample data
Theory:
Accounts for facts and suggest how they are related to each other. A framework of ideas that
provides an explanation of something
The theory – if true – implies what we should observe under certain specific circumstances
Psychological research:
Testing theories of human behaviour / testing of theories against observations
Purpose is to gather and organise data
Build theories and test them empirically, through observation
Theory: A network of postulated relations between constructs / concepts / variables
Constructs:
building blocks of theory
theoretical in nature
deliberately created / proposed to explain certain observations
often refer to a hypothetical aspect of a person / situation
cannot be observed, has to be inferred from behaviour
i.e. anxiety = sweat, empty sensation in stomach, heart palpitations are all symptoms caused
by unseen underlying process
Anxiety = LATENT variable - hidden / intervening
Behaviour instances of sweating / palpitations = MANIFEST variables
Variable aka indicators / referents / observable consequences / implications
Based on the observable behaviour of an abstract construct / concept – we can derive an
anxiety score
To arrive at a score – we must provide a measured operational definition of the construct; a
measurement model for each construct
By identifying observable behavioural instances of a construct – one can measure it
DEPENDENT VARIABLE - Variable that is influenced – the EFFECT
INDEPENDENT VARIABLE – Variable that influences – the CAUSE
OPERATIONAL DEFINITION : Specifying observable instances of a construct
2 KINDS
1. THEORETICAL definition of a construct – where a construct is defined in terms of other
constructs
2. OPERATIONAL definition of psychological constructs – constructs defined in terms of
observable instances (necessary for measurement) - allows us to bridge the gap between
theoretical constructs and observations by spelling out what must be done to measure the
construct
OPERATIONALISING OF CONSTRUCTS – process followed to make abstract concepts
empirically observable – making them measurable – transforming theoretical constructs into
empirical constructs
INDICATOR – an observable measure of a construct
, Intelligence = construct
Vocab and numerical competence = indicators of the construct intelligence
Based on indicators one can specify behaviours associated with the constructs
NOMINAL LEVELS OF MEASUREMENT
Labels – just a name
Can’t measure the difference
Discrete – distinct & separate
Mutually exclusive - choosing one automatically excludes the other
Exhaustive – makes provision for all possible variables
ORDINAL LEVELS
When data needs to be ranked in an order of importance
Least to most / always to never
The degree of difference cannot be measured
INTERVAL
Same characteristics of nominal and ordinal BUT – can measure the difference or intervals
between 2 points
Numbers have a value but no absolute zero point
RATIO
Highest level of measurement
Length / weight / time
The HYPOTHESIS
A statement of relation (or absence thereof) between 2 / more constructs or variables
Y = exam performance – dependent variable
X = Independent variables (cause for performance)
U = unknown causes
There are multiple influences on Y
The hypothesis
- will give a rule that associates values of one construct with those of another construct
- will suggest the population for which the relation holds
Operational forms of the hypothesis
Operational hypothesis: using observations of measurable forms of the construct
A = General hypothesis: “Anxiety influences performance negatively”
B = “test anxiety influences exam performance negatively”
C = Operational hypothesis: “the higher i-pat anxiety scores, the poorer PYC3704 students’
performance”
In C, construct anxiety has been operationally defined as i-pat and performance