Scientific Processes

• Aims


  Identifies the purpose of the investigation
• Aims


  • Peterson and Peterson investigated the duration of STM when maintenance rehearsal was prevented
• Hypothesis


  Mainly called an alternative hypothesis (umbrella term), but also called experimental hypothesis/research hypothesis
• Hypothesis


  • Precise, testable statement of what the researchers predict will be the outcome of the study
  • Must be written as a statement and not a question
  • Hypothesis must incorporate independent variable and dependant variable
  • Operationalised (IV and DV have to be measurable)
• Types of hypotheses


  • Directional
  • Non-directional
• Directional hypothesis


  • Predicts the nature of the effect of the IV on the DV
  • Selected when previous research has been done
• Directional hypothesis


  • Adults will correctly recall more words than children
• Non-directional hypothesis


  • Predicts that the IV will have an effect on the DV, but the direction of the effect is not specified
  • Selected when hypothesis is new idea
• Non-directional hypothesis


  • There will be a difference in how many words are recalled by children and adults
• Types of experimental/correlational hypotheses

  • Directional - Experiment
  • Directional - Correlational Study
  • Non-Directional - Experiment
  • Non-Directional - Correlational Study
• Directional - Experiment


  • Athletes who have a training partner are likely to score higher on a question measuring motivation levels than athletes that train alone
• Directional - Correlational Study


  • There will be a strong positive correlation between athletes motivation questionnaire score and the number of partners athletes train with
• Non-Directional - Experiment


  • There will be a difference between questionnaire score in athletes who train alone compared to athletes that train together
• Non-Directional - Correlational Study


  • There will be a relationship between questionnaire scores and number of training partners
• Null hypothesis


  • Must accompany an alternative hypothesis whether it is directional or non-directional
  • There will be no difference _________ and any differences that do occur are due to chance
• Null hypothesis


  • H1 -> Learning in a warm room will result in higher test score than learning in a cold room

  H0 -> There will be no difference in test score when learning in a cold/warm room. Any difference that occur are due to chance
• Null hypothesis


  • Helps researchers decide between two interpretations
• Sample


  Group of participants who take part in the investigation
• Target Population


  Total group of individuals from which the sample might be drawn from
• Generalisability


  The extent to which we can apply the findings of our research to the target population we are interested in
• Random Sampling


  • Gives every person from the target population an equal chance of being selected
  • Every name is given a number and a list of random numbers is used to select the sample either manually or using a computer
• Random Sampling


  1. Select participants

  2. Every participant is given a number/they are entered into a computer name/number random generator

  3. If manual (place all names on a hat) and select/if compuyer generated they are selected

  4. Each placed in allocated condition of the experience,to until all participants have been selected
• Random Sampling


  • Can be representative
  • Can be unrepresentative
• Opportunity Sampling


  Made up of anyone who is willing and available to take part at the time of the study taking place
• Opportunity Sampling


  • Most common sampling technique in psychological research
• Evaluations of Opportunity Sampling


  Quick, convenient and economical
• Evaluations of Opportunity Sampling


  • Researchers simply need to approach individuals who are in the target population and ask them and then for their participation in the study
• Evaluations of Opportunity Sampling


  Less planning and preparation required, leading to fewer delays in the research process and less money
• Evaluations of Opportunity Sampling

  Can be unrepresentative
• Evaluations of Opportunity Sampling


  • If a study in a city centre is conducted during work hours, this sample will not represent individuals who work, go to school, college etc.
• Evaluations of Opportunity Sampling


  Samples can lack population validity
• Systematic Sampling


  Uses a predetermined system to select every participant, such as every 'n'th (ex. 20th, 16th, 4th) person from a list (ex, register)
• Systematic Sampling


  • Numerical interval applied consistently
• Stratified Sampling


  • Subgroups (strata) are identified in a population
  • Participants are obtained from each of the strata in proportion to the occurrence of the population
  • Selection from the strata is done using a random technique
• Volunteer Sampling


  • Consists of individuals who have volunteered to take part in research
  • Researchers may advertise for participants on notice boards or in newspapers