Research methods
Contents
Basics Pg 2
Types of experiment Pg 2
Aims and hypothesis Pg 3
Experimental designs Pg 4
Reliability and validity Pg 5
Sampling Pg 6
EVs and bias Pg 7
Pilot studies Pg 8
Observational design Pg 8
Ethics Pg 10
Questionnaires Pg 11
Interviews Pg 12
Levels of measurement Pg 12
1
, Basics of research methods
Quantitative data numerical data (objective)
Qualitative data words or pictures (subjective)
The experimental method is a research method that assigns pts to different conditions and
changes variables to create an effect. A variable is an object, characteristic or event that can
change or vary in some way.
Manipulating the independent variable causes a change in the dependent variable. There are
different types of variables:
- Independent (one that is changed)
- Dependent (one that is measured)
- Extraneous (a variable that could have an effect on
the DV – excluding the IV)
- Confounding (an extraneous variable that has not
been controlled – confound the result)
Types of extraneous variables:
1. Participant variables (intelligence, dyslexia, age, gender, emotional state etc)
2. Situational variables (temperature, time of day, noise etc)
3. Experimenter variables (mood, how they express themselves, personal attributes,
knowledge of previous experiments – might interpret the data w conscious or
unconscious bias)
Operationalisation being able to define variables simply + easily into quantitative
e.g. stress levels could be defined by measure of blood
pressure, heart rate, etc.
A problem with operationalisation of complex variables is that it normally only measures one
aspect of the variable.
Baddeley (1966), Tyler (1979) and Smith (1979) did investigations into how memory was
affected by acoustic similarity, how much the task had been processed and location of recall.
The IV is something that is manipulated to bring about a change in measured behaviour, the
DV. Control is achieved when, other than the IV, all other variables that could affect the DV
(extraneous variables) are at a constant.
Types of experiment
There are four types of experiment – laboratory, field, natural and quasi.
The IV Environment
Laboratory Manipulated by experimenter Controlled
Field Manipulated by experimenter Natural
Natural Occurs naturally Controlled or natural
Quasi Based on innate difference Controlled or natural
2
Contents
Basics Pg 2
Types of experiment Pg 2
Aims and hypothesis Pg 3
Experimental designs Pg 4
Reliability and validity Pg 5
Sampling Pg 6
EVs and bias Pg 7
Pilot studies Pg 8
Observational design Pg 8
Ethics Pg 10
Questionnaires Pg 11
Interviews Pg 12
Levels of measurement Pg 12
1
, Basics of research methods
Quantitative data numerical data (objective)
Qualitative data words or pictures (subjective)
The experimental method is a research method that assigns pts to different conditions and
changes variables to create an effect. A variable is an object, characteristic or event that can
change or vary in some way.
Manipulating the independent variable causes a change in the dependent variable. There are
different types of variables:
- Independent (one that is changed)
- Dependent (one that is measured)
- Extraneous (a variable that could have an effect on
the DV – excluding the IV)
- Confounding (an extraneous variable that has not
been controlled – confound the result)
Types of extraneous variables:
1. Participant variables (intelligence, dyslexia, age, gender, emotional state etc)
2. Situational variables (temperature, time of day, noise etc)
3. Experimenter variables (mood, how they express themselves, personal attributes,
knowledge of previous experiments – might interpret the data w conscious or
unconscious bias)
Operationalisation being able to define variables simply + easily into quantitative
e.g. stress levels could be defined by measure of blood
pressure, heart rate, etc.
A problem with operationalisation of complex variables is that it normally only measures one
aspect of the variable.
Baddeley (1966), Tyler (1979) and Smith (1979) did investigations into how memory was
affected by acoustic similarity, how much the task had been processed and location of recall.
The IV is something that is manipulated to bring about a change in measured behaviour, the
DV. Control is achieved when, other than the IV, all other variables that could affect the DV
(extraneous variables) are at a constant.
Types of experiment
There are four types of experiment – laboratory, field, natural and quasi.
The IV Environment
Laboratory Manipulated by experimenter Controlled
Field Manipulated by experimenter Natural
Natural Occurs naturally Controlled or natural
Quasi Based on innate difference Controlled or natural
2
