Research methods

• Research methods


  Systematic procedures used to observe, describe, predict and explain behaviour and mental processes
• Hypotheses

  Four types of hypotheses:

  • Null Hypotheses
  • Alternative Hypotheses
  • One-tailed
  • Two-tailed
• Null Hypotheses


  These predict that no difference will be found in the results between the conditions. Typically written 'There will be no difference'
• Alternative Hypotheses 


  These predict that there will be a significant difference in the results between the two conditions. Also known as experimental hypothesis
• One-tailed hypotheses 


  These state the specific direction the researcher expects the results to move in e.g. higher, lower, more, less
• Two-tailed hypotheses 


  These state that a difference will be found between the conditions of independent variable but does not state the direction or relationship. Typically these are always written 'There will be a difference'
• Hypotheses summary


  Once research is conducted and results found, psychologists must accept one hypothesis and reject the other - so if a difference is found, the psychologist would accept the alternative hypothesis and reject the null, opposite applies if no difference is found
• Sampling


  The process of selecting a representative group from the population under study
• Representative


  The extent to which a sample mirrors a researcher's target population and reflects its characteristics
• Generalisability


  The extent to which their findings can be applied to the larger population of which their sample was a part
• Volunteer sampling


  Consists of people who have volunteered to be in the study

  + Often achieves a large sample size via reaching a wide audience

  -May all display similar characteristics
• Opportunity sampling


  Participants who are both accessible and willing to take part are targeted e.g. employees from a local employer near the lab

  + Method is easy and inexpensive

  -Consequent sample may not be representative
• Stratified sampling 


  Here the sampler divides or 'stratifies' the target group into sections, each showing a key characteristic which should be present in the final sample. Then each of these sections is sampled individually

  + Avoids the problem of misrepresentation

  -Takes more time and resources

  -Care must be taken to ensure each key characteristic is selected
• Systematic sampling


  Chosen for selecting from a target group e.g. every fourth person in a list could be used in the sample. Differs from random sampling in that it does not give an equal chance of selection to each individual in target group

  + Offers an unbiased chance

  -If list not randomised, bias may be present
• Random sampling


  Gives every member of the target group an equal chance of being selected for the sample

  + Reasonable chance of achieving a representative sample

  -Small minority groups may distort results

  -Can be impractical
• Snowball sampling


  Researchers find a few participants, and then ask them to find participants themselves and so on
• Quota sampling


  Researchers will be told to ensure the sample fits a certain quota, for example they might be told to find 90 PPs. with 30 of them being unemployed
• Independent variable

  The one the experimenter manipulates (the thing that changes between the conditions the participants are place into) assumed to have a direct effect on the dependent variable
• Dependent variable


  The thing that the experimenter measures
• Operationalisation of variables


  Means making them quantifiable
• Extraneous variables 


  All variables which are not independent but that could affect the results of the experiment
• Demand characteristics 


  A type of extraneous variable that occurs if the PPs work out the aims of the study, they may begin to act a certain way
• Experimental design


  Refers to how participants are allocated to each condition of the independent variable, such as control or experimental group
• Independent design 


  Each participant is selected for only one group
• Matched-pairs design


  Each participant is selected for only one group, but the participants in the two groups are matched for some relevant factor or factors
• Repeated measures design


  Each participant appears in both groups, so that there are exactly the same participants in each group
• Order effects


  Occurs when participants' responses in the various conditions are affected by the order of conditions to which they were exposed
• Counterbalancing


  Best way of preventing order effects from disrupting findings

  Usually presented as ABBA
• Lab experiments 


  Conducted in a well-controlled environment, therefore accurate and objective measurements are possible
• Field experiments 


  Conducted in the everyday environment of the participants. The experimenter still manipulates the IV, but in a real-life setting
• Natural experiments 


  When a naturally occurring IV is investigated that isn't deliberately manipulated, it exists anyway. Participants are not randomly allocated, and the natural event may only occur rarely
• Case studies 


  In depth investigations of a person, group, event, or community. It uses information from a range of sources, such as from the person concerned and also their family and friends
• Correlation 


  Means association; it is a measure of the extent to which two variables are related.
• Positive correlation


  If an increase in one variable tends to be associated with an increase in the other
• Negative correlation


  If an increase in one variable tends to be associated with a decrease in the other
• No correlation 


  Occurs when there is no relationship between variables
• Structured interviews 


  A fixed, predetermined set of questions is put to every participant in the same order and in the same way
• Unstructured interviews 


  There are no set questions, and the participant can raise whatever topics he/she feels are relevant and ask them in their own way. Questions are posed about participants answers to the subject
• Open questions


  Are designed to encourage a full, meaningful answer using the subject's own knowledge and feelings - Open to any answers
• Closed questions 


  Can be answered with a simple "yes" or "no" or specific information, limiting the depth of response