psychology things i often forget

• what is a directional hypothesis?


  states the direction of the difference or relationship (e.g. boys are more helpful than girls).
• what is a directional hypothesis otherwise called?

  1 tailed
• what is a non directional hypothesis?


  hypothesis that does not predict the direction of the difference or relationship (e.g. girls and boys are different in terms of helpfulness).
• what is a non directional hypothesis otherwise called?

  two tailed
• what does chi squared measure?

  the difference between an observed value and the expected value

  a test of difference or association
• what data does chi squared use?

  categorical/nominal data
• what is categorical/nominal data?

  data which can only be in certain categories eg blue eyes, green eyes
• what experiment design is chi squared used on?

  independent groups
• what does chi squared show?

  if results are significant
• what does the t-test measure?

  the difference between two means
• what design does a t-test use?

  it can use repeated (matched pairs, repeated measures) and independent (related t-test or unrelated t-test)
• what does t-test show?

  if some a treatment affects a population more than something else

  to see if two groups differ from each other
• when to use a sign test?

  when investigating a difference, repeated design, nominal data
• what is discrete data?

  data with a limited number of responses (do you have siblings? yes/no)
• what is continuous data?

  data which can have any value (eg weight)
• what data does spearmans test use?

  ordinal
• what is ordinal data?

  data which has been ordered/ranked
• what is a type 1 error?

  when an investigator rejects a null hypothesis that is actually true
• what is a type 2 error?

  when an investigator accepts a null hypothesis that is actually false
• what does spearmans test?

  correlation
• what hypothesis does spearmans need?

  null and directional
• when do you use a non directional hypothesis?

  when there is no other research in the field that could suggest a direction
• when do you use a directional hypothesis?

  when there is previous research in the field which suggests a direction
• what is reliability?


  consistency
• what is face validity?


  a simple way of assessing validity

  to assess if something seems to measure what it claims to measure
• define operationalisation?


  operationalisation involves clearly defining dependant variables to enable them to be measured
• how to write a discussion?

  • talk about significance of findings
  • how they are/aren't significant
  • influence of the findings
  • possibilities of a type 1/2 error
• how to carry out an inter-observer reliability observation?


  -agree the interpretation of categories beforehand

  -observe the same person/target at the same time but record independently

  -correlate the recordings with appropriate stats test
• what is opportunity sampling?


  Non-random sampling method where participants are selected based on their availability and willingness to participate.