Research methods

• what is an independent variable


  the variable the researcher changes or manipulates
• what is the dependent variable


  the variable the researcher records and mesaures the effect of this change
• why should all other variables (extraneous variables stay the same)

  so the researcher can be confident that the cause of the effect on the dv was the IV alone and not any other variable
• operationalising variables

  how you will change / measure the variables
• how can an investigation be further operationalised


  more details of the investigation are given , such as the number of questions on the test
• what is a directional hypothesis


  states the direction the relationship that will be shown between the variables
• examples of directional hypothesis 


  Boys will use more swear words then girls
• what is a non directional hypothesis


  two tailed hypothesis which simply states that there is a difference between the conditions or different groups of people but does not state the difference
• example of a non directional hypothesis 


  there is a difference in the amount of swear words used by boys and girls
• a null hypothesis 


  states that there is no difference between the conditions or groups of people
• aim


  the purpose of the study
• hypothesis 


  a testable statement
• extraneous variable 


  any other variable which is not the IV that effects the DV but doesnt vary systematically with the IV
• examples of extraneous variable


  lighting in a lab, age of participants
• how do extraneous variables effect the investigation


  harder to detect the cause and effect
• cofounding variables 


  same as extraneous variable however it does vary systematically with the IV
• examples of cofounding variables


  time of day e.g in a sleep study the people who did the test later may be more tired and therefore do worse
• 4 types of extraneous variables

  situational variables

  participant variables

  investigator effects

  demand characteristics
• what is situational variables

  aspects of the environment that effect a participants behaviour e.g noise , lighting conditions
• participant variables

  ways in which participants vary from each other e.g mood , intelligence
• demand characteristics 


  any cue the researcher may give which makes the participant feel like they can guess the aim of the investigation
• what do demand characteristics cause 


  participants can act differently e.g please u and screw u effect
• investigator effects 


  are the ways in which researchers unconsciously influence the results of research
• examples of investigator effects 


  biased in their interpretation of the data and find what they expect to find

  less obvious personal characteristics of invesitigators like accent and tone

  the design of the study
• ways of dealing with extraneous variables 


  single blind design

  double blind design

  experimental realism
• what is experimental realism 


  if the researcher makes the task sufficiently engaging the participant will pay attention to the task and not the fact that they are being observed
• how to overcome investigator effects 


  standardisation- instructions written in a particular way e.g a format in which they can be read out and a check at the end so participants know what they have to do
• validity

  the extent to which a study measures what it intends to measure
• internal validity 


  whether the effects observed in the experiment are due to the manipulation of the IV and no other variable
• mundane realism


  how realistic the task is , do you get asked to do this in everyday life
• external validity 


  how well you can generalise from the research participants to people , places and times outside the study
• ecological validity 


  how well you can generalise the study to different settings and environments
• population validity 


  how well the sample used can be generalised to the population as a whole
• temporal validity 


  how valid the conclusions of the study over time
• pilot studies 


  small scale investigations to indetify potential problems with the design or method
• examples where pilot studies are useful


  participants may not understand the question , bored if there are too many tasks or questions
• confederates 


  another person to play a role in an experiment
• repeated measures design


  the same participants take part in all conditions of the IV
• advantages of repeated measures 


  eliminates participant variables

  fewer participants needed so less time consuming trying to find
• disadvantages of repeated measures design


  order effects e.g boredom