3.2 - Scientific Processes

• What is an aim?

  • a clearly phrased general statement about what the investigator intends to research
• What is a hypothesis?

  • a clear testable statement including levels of IV and DV
• What is a null hypothesis?

  • there is no change/difference in the measurement of the DV as a result of the manipulation of the IV
• What is an alternative hypothesis?

  • there is a difference in the DV as a result of the IV
• What are the types of alternative hypotheses?

  1. Non directional (two tailed) - states there is a difference in the measurement of the DV but not the direction the result will go
  2. Directional (one tailed) - there is a difference in the DV and the direction in which the results will go - only used if there is previous research
• What are the types of sampling?

  1. Random
  2. Opportunity
  3. Systematic
  4. Stratified
• What is random sampling?

  • each member of the target population has an equal chance of being selected
  • ADV - avoids researcher bias
  • may produce an unrepresentative sample
  • can be difficult and time consuming to conduct
• What is systematic sampling?

  • a systematic method is devised to choose a sample (every nth pp)
  • ADV - avoids researcher bias
  • quick method with student registers
  • DIS - could produce an unrepresentative sample
  • getting a large target sample can be difficult
• What is opportunity sampling?

  • researcher directly asks members of populations who they have access too and are familiar with
  • ADV - quick and cheap to conduct
  • DIS - researcher bias - preferred result
  • likely to be unrepresentative
• What is stratified sampling?

  • a sample that is representative of target population
  • ADV - representative and avoids researcher bias
  • DIS - time consuming and not every possible characteristic can be included
• What is the difference between a population and a sample?

  • A population is the entire group that you want to draw conclusions about. A sample is the specific group that you will collect data from.
• What is a pilot study?

  • small scale trial run of an investigation
  • aim is to check that procedures, materials work and can make changes if necessary
• How is a pilot study conducted?

  • A pilot study involves running the planned methodology but with a much smaller number of participants.
• What is a single blind pilot study?

  • researcher is aware of the aim of the study
• What is a double blind study?

  • researcher and pps are not aware of the aim of the study
• What is an independent measures design?

  • different pps complete in each of the conditions
  • produces unrelated data - data from one condition cannot be paired with data from another
  • ADV - pps are less likely to work out the aim which reduces demand characteristics
  • less order effects
  • DIS - need double the pps for same amount of data
  • pp's variables between conditions
• What is a repeated measures design?

  • the same pps compete in each of the two experimental designs
  • produces unrelated data as each pps score in one condition can be paired with data in another condition
  • ADV - only need half pps for same amount of data
  • pp variables are not a problem
  • DIS - more likely to work out aim - demand characteristics
  • order effects - due to fatigue or practice - counterbalancing can reduce use ABBA format
• What is matched pairs design?

  • different pps compete in each of the conditions of the experiment
  • first assessed and then ranked on a characteristic and top 2 are randomly assigned to conditions (produces related data)
• Evaluation of matched pairs design -

  • ADV - reduces pps variables
  • reduces order effects
  • DIS - takes longer to set up and need twice as many pps
  • pps are similar but not identical so there may still be pp variables
• What are behavioural catergories?

  • behaviours need to be clearly identifiable and measurable
  • choice of behaviour to record and how they are measured
• What is time sampling?

  • researcher records relevant behaviour at set time intervals
  • ADV - more flexible and able to record unexpected behaviour
  • DIS - can miss behaviour that happens outside time periods
• What is event sampling?

  • researcher records every time a behaviour records from a list of behavioural catergories
  • DIS - may miss relevant behaviour if too many happen at once
  • ADV - any rare behaviours are noted down because of the lack of time period
• What is an extraneous variable?

  • any variable not being investigated that has the potential to affect the outcome of a research study.
• What is a confounding variable?

  • factors other than the independent variable that may cause a result.
• What is operationalisation?


  • A variable is operationalised when it has been turned in to something that can be measured
  • turning abstract concepts into measurable
• How is control in research done?

  1. Randomisation
  2. Random Allocation
  3. Counterbalancing
  4. Standardisation
• What is randomisation?


  • deliberate avoidance of bias on the part of the researcher in order to keep the research as objective as possible
• How is randomisation used in research?

  1. PPs are randomly assigned to one condition of the IV (randomly selecting out a hat)
  2. Random allocation to condition to ensure that no bias has entruded over which condition pps take
  3. If the procedure involves a list of words, digits or images then the list must be randomly decided
• What is counterbalancing?


  • one group completes the conditions by condition A followed by condition B
  • other group - Condition B followed by condition A and is used to control for order effects
• What is standardisation?


  • used to describe the identical procedure set up in an experiment
  • allows research to be replicated and reliable
• How is standardisation conduced in experiments?

  1. Briefing prior to procedure (consent form) and debrief
  2. Number of pps per condition is equal
  3. Timings - each condition of IV should run for the same amount of time
  4. Materials - identical materials must be used
• How to conduct a systematic sample?

  • put names into a sampling frame and establish how they will be ordered
  • select every nth participant
• How to conduct a stratified sample?

  • establish the proportional sample and strata (ratio)
  • randomly pick from the strata
• What are demand characteristics?

  • cues that might indicate the aim of the study to participants
  • can overcome with deception or independent measures design
• What are investigator effects?

  • when a researcher unintentionally or unconsciously influences the outcome of the research
• What are ethical issues?

  1. Informed Consent
  2. Deception
  3. Right to withdraw
  4. Protection from harm
  5. Confidentiality
  6. Debriefing
• How to deal with ethics?

  • cost benefit analysis - role is to make judgements about the costs and benefits of an individual
  • consent - consent letter or form
  • deception/harm - given a debrief or right to withdraw
  • confidentiality - maintaining anonymity
• What is a peer review?

  • when before publication, an author's scientific paper is assessed by peers
• Strengths of peer review -

  • second opinion to review or check data to ensure reliability
  • aids in scientific communicatio
• Limitations to peer review -


  • journals may struggle to find suitable peers
  • bias due to proffesional rivalry