RESEARCH METHODS

SCIENTIFIC METHOD:

  1. identify area of research
  2. collect information
  3. identify the research question and formulate a hypothesis.
  4. design a research method
  5. collect and analyse the data
  6. draw a conclusion
    7 report findings
    8 test the conclusion.

VARIABLES:

independent variable: variable manipulated by the experimenter.

dependent variable: the property that is measured in the research.

extraneous variables: a variable other than the IV that could cause changes in the value of the DV.

confounding variables: a variable other than the IV that has a systematic effect on the value of the DV.

SAMPLING:

Random Sampling:

  • every member of the population has an equal chance of selection.
  • eg. random number generator.

Stratified Sampling:

  • dividing population into categories and selecting at random in proportions equivalent to population.
    Example:
- 30000 VCE psychology students , 24000 females, 6000 males. 
- therefore sample includes 240 females and 60 males.

STRENGTHS:

  • gives representative sample - participant variables spread in same proportion as in population.

WEAKNESSES:

  • difficult to achieve - the larger the population, the harder it is to list all individuals.

STRENGTHS:

  • eliminates the effect of the variable on which the sample is stratified.

WEAKENSSES:

  • time consuming; expensive

PARTICIPANT ALLOCATION:

Convenience Sampling:

  • picking whoever is available at the time.

STRENGTHS:

  • quick, easy, cheap - this is the most common method of sampling.

WEAKNESSES:

  • bias in sample

experimental group: the group exposed to the IV.

control group: the participants who are not exposed to the IV.

RANDOM ALLOCATION:

  • all participants who have been selected for an experiment (the sample) have an equal chance of being in the E-group or the C-group.

EXPERIMENTAL DESIGNS:

REPEATED MEASURES DESIGN:

  • each participant is part of both the E-group and the C-group.
  • a method of overcoming order effects is counterbalancing - half of the participants do IV then DV and other half do DV then IV.

ADV:

  • confounds caused by participant variables are eliminated.
  • possible to use fewer participants.

DIS:

  • Repeated measures design takes a long time, therefore drop-outs are likely
  • order effects: participants may perform better when doing the task a second time or they might do worse because of fatigue or boredom.

MATCHED PARTICIPANTS DESIGN:

  • a researcher identifies a variable that is a likely confound, and eliminates the effects of the variable by ranking participants in accordance with their scores on the variable and then allocated to a specific group.
  • eg. ranking by IQ. Top IQ participants are split, 2nd Top are split etc.

ADV:

  • the procedure can be done at once and therefore drop outs are unlikely.

DIS:

  • the procedure needs a large number of participants to ensure that the spread of participant variables in the sample will match the spread in the population.

INDEPENDANT GROUPS DESIGN:

  • allocates participants to the C-group or E-group at random.

ADV:

  • can be done at once and drop outs are unlikely.

DIS:

  • the procedure needs a large number of participants to ensure the spread of participant variables in the sample will match the spread in the population.

CONTROLLING PARTICIPANT AND EXPERIMENTER EFFECTS:

PLACEBO EFFECT:

  • refers to the particpants behaviour being influenced by their expectations of how they should behave, caused by the belief that they have received some treatment.
  • can be eliminated by using a single-blind procedure - allocating participants to groups in such a way that they do not know whether they are in the E-group or C-group.

EXPERIMENTER EFFECT:

  • refers to the outcome of an experiment being unintentionally (or intentionally) influenced by the experimenter.
  • it occurs, for example, if the experimenter treats the members of the E-group and the C-group differently.
  • can be eliminated by using a single-blind procedure, where the experimenter is blind. OR by using a double blind procedure where neither the experimenter or the participants are aware of which is the C-group and E-group.

TYPES OF DATA:

qualitative data: refers to characteristics e.g. happy, easy etc.

quantitative data: refers to measurements.

subjective data: based on opinion.

objective data: measured according to an identifiable external criterion.