Theory
Hypothesis
Method
Sample
Process of Results
Interpretation of Results
Conclusion
Revise Theory?
Theory
- explain and predict a variety of phenomenon in general terms
- made up of different ideas/models
Hypothesis
- a statement
- Null Hypothesis and Alternative Hypothesis
Three Hypothesis Conditions
- Predict that a difference will occur between one group and another
- A precise statement with an IV and DV
- Refutable - capable of being wrong
Independant Variables - the variable that the researcher manipulates.
Dependant Variables - the behaviour of the subject.
Dr. I. Vee likes to experiment on his friend Davey.
"The Herion Addict"
The doc says I'm a IV Drug User
Whether I am high or die
Is dependant on how much I use
Examples
"Smoking causes cancer"
IV - Smoking (the Experimentor will control group of smokers and non-smokers)
DV - Cancer (the "behaviour" of subject)
"Materal deprivation in the first five years of life in delinquent behaviour during adolescence"
IV - Materal Deprivation in first 5 years
DV - Deliquent behaviour in adolescence
"People who have low levels of intelligence watch three soap operas regularly"
IV - Hours of TV watched
DV - Intelligence
Operationalisation
- Attempting to define a variable in order to measure it's occurance.
Example
"Younger girls talk more during lessons than older boys"
IV - Age and Gender
DV- Talking
Operationalise: definition of young and old; the amount of talking
"Eating cheese before bed causes nightmares"
IV - Eating cheese
DV - Nightmares
Operationalise: what classes as a nightmare? how much cheese? type of cheese? delay before bed?
Null Hypothesis
- No observable effect on DV
Alternative Hypothesis
- Predicts affect on DV
Types of Hypothesis
One tailed - ONE OUTCOME Directional Hypothesis
- predicts direction of result
"Bullying has a NEGATIVE effect on exam performance"
Two tailed Non-directional Hypothesis
- Predicts effect but not direction
"Being bullied WILL AFFECT exam performance"
The Experiment
- where a researcher manipulates the independant variable to see if it has an effect on the dependant variable.
The Three Conditions
- Generalisation - must be able to generalise results to the whole population (biggger sample size helps this)
- Replication - results set down so it can be repeated exactly (reliable experiement - same results all the time)
- Validity - measure what you think you are measuring!
E.G. "Middle aged men who have more sex live longer" Does sex REALLY cause longevity? what else? diet, exercise? etc
Ethics
Consent
- participants informed of the nature of the experiment. Particularly if information will influence willingness to take part.
- with children, special safeguards must be used
- under 16's parents consent
Deception
-cannot withhold information if it affects decision to take part
- if nessesary, consider alternative procedure, give sufficient information as soon as possible, consult experienced researcher
Debreif
-participants should understand the research
-discuss with participants
Withdrawl
-inform of "right to withdraw" procedure
-before, during or after investigation
-data MUST be destroyed
Confidentiality
-information is confidential unless informed beforehand
-information must not be identifiable
Protect From Harm
-participants must not experience any distress that is outwith any level they expect in everyday life
-contact number if they experience stress or questions
Experimental and Control Groups
Experimental group experiences the prescence of an IV
Control group comparison experiences an abscence of IV
"Smoking causes Cancer"
Experimental Group - those who smoke
Control Group - those who do not smoke
Extraneous Variables
- variables that may cause the result other than the independant variable
"Puddles cause umberella's to go up"
IV - puddles
What else? - RAIN!
Three Types of Extraneous Variable
- Participant - intelligence, memory, personality, mood, motivation
- Situational - light, temperature, time of day, noise, place
- Investigator
Investigator Variables
- Demand Characteristics - participant searches for cues to work out how to behave. They behave artifically because they think it's DEMANDED
- Experimenter Effect - characteristics of the experimenter (age, sex, race, behaviour)
- Experimenter Bias - experimenter's expectations affect participant's performance
The Hawthrone Effect
George Elton Mayo et al (1924 - 1932)
Aim - find out which variables affected employees work
Hawthorne Plant - Western Electric Company - Illinois
Manipulated work enviornment (light, temperature etc)
All manipulation did not effect work performance.
Conclusion - workers felt special to be chosen for experiment. Increased status amongst workers
Confounding Variable
- a variable that definately DOES affect the IV
Sampling Methods
Random Sampling
People in the target population have an equal chance of being chosen.
Advantages
- Unbiased sample
-
Disadvatanges
- Impractical for large sample sizes
- Time consuming
Stratisfied Random Sampling
Breaking down the population into sub-groups (e.g. age) then random participants are taken from those sub-groups to represent the population
Advantages
- representative of population
Disadvantages
- time consuming
- lack of participant details can make this challenging
Quota Sampling
Once subgroupd have been identified, the researcher picks people from the groups.
Advantages
- less time consuming than stratisfied where the subgroups are randomly selected
Disadvantages
- No proof sample represents population
Systematic Sampling
Researcher uses a system to pick participants from the population
e.g. picking every 10th person from a list
Advantages
- whole population is easily sampled
Disadvantages
-
Opportunity Sampling
Researcher picks those who are willing and able to participate
OR
Participants who take the opportunity to do the experiment
Advantages
- easy to carry out
- cheap
Disadvantage
- biased sample
Self- Selected Sampling
Participants who respond to adverts, or volunteer to take part in an experiment.
Advantages
- cheap
- quick
- an opportunity to reach a wide population
Disadvantages
- biased sample - those who participant have a hidden agenda!
Snowballing
Word-of-mouth ; researcher tells participants, who then tell friends/family, who will then participant
Advantages
- quick way of gathering participants
- good for reaching hard-to-get participants
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