Key Terms

• Aim

  developed from theories that are general statements that describe the purpose of the investigation in the present tense
• Alternative/Experimental Hypothesis

  the statement that is made at the start of a study and clearly states the relationship between variables as stated by the theory
• Null Hypothesis

  states that there is no relationship between the variables being studied
• Directional Hypothesis

  • makes clear the sort of difference that is anticipated between conditions or two groups of people
  • used when previous research has been done and shown that outcome of the study
• Non-directional hypothesis

  there is a difference between conditions pr groups of people but the nature of the difference is not specified
• Independent variable

  the variable that the researcher changes
• Dependent variable

  the variable that is recorded or measured
• experimental condition

  the condition that measures the effect the independent variable has on the dependent variable
• control condition

  the condition that we can base results on
• operationalisation

  turning abstract concepts into measurable observations
• independent group design

  participants are allocated to different group where each group represents one experimental condition
• repeated measures design

  all participants take part in all conditions of the experiment
• matched pairs design

  • pairs of participants are first matched on some variables that may affect the dependent variable
  • then one member of the pair is assigned to condition A and the other condition B
• laboratory experiment

  an experiment that takes place in a controlled environment within which the researcher manipulates the independent variable and records the effect on the dependent variable, whilst maintaining strict control of extraneous variables
• field experiment

  takes place in a natural setting within which the researcher manipulates the independent variable and records the effect on the dependent variable
• natural experiment

  an experiment where the change in the independent variable is not brought about by the researcher but would have happened even if the researcher had not been there
• quasi-experiment

  the researcher takes advantage of a pre-existing independent variable, the variable would have changes even if the experimenter was not interested (the IV is natural)
• target population

  a group of people who are the focus of the researcher's interest, from which a smaller sample is drawn
• bias

  when certain groups may be over or under represented within the sample selected, this limits the extent to which generalisations can be made to the target population
• random sampling

  all members of the population have an equal chance of being selected
• systematic sampling

  when every nth number of the target population is selected
• stratified sampling

  the composition of the sample reflects the proportions of people in certain sub groups within the target population or the wider population
• opportunity sampling

  when researchers select anyone who is willing and available
• volunteer sampling

  participants selecting themselves to part of the sample
• demand characteristics

  any cue from the researcher or from the research situation that may be interpreted by the participants as revealing the purpose of the investigation. This may lead to a participant changing their behaviour within the research situation
• investigator effects

  any effect of the investigator's behaviour in the research outcome
• randomisation

  the use of chance in order to control for the effects of bias when designing materials and seceding the order of conditions
• standardisation

  using exactly the same formalised procedures and instructions for all participants in a research study
• pilot studies

  a small scale version of an investigation that takes place before the real investigation is conducted. the aim is to check that procedures, material, measuring scales work and to allow the researcher to make changes or modifications if necessary
• double blind studies

  neither the participants nor the researcher is aware of the aims of the investigation
• single blind studies

  the participants aren't told the aim of the study
• questionnaires

  a set of written questions used to assess a persons thoughts and/or experiences
• open questions

  do not have a fixed range of answers and respondents are free to answer in any way they wish
• closed questions

  offer a fixed number of responses
• quantitative data

  easy to analyse but may lack depth and detail associated with open questions
• qualitative data

  rich in detail and depth but may be difficult to analyse
• interview

  a live encounter where one person asks a set of questions to assess an interviewee's thoughts and/or experiences
• structured interview

  pre-set questions in an interview
• unstructured interview

  questions develop as the interview goes along
• semi-structured interview

  list of questions but interviewers are free to ask follow-up questions when they feel it's appropriate