key science skills

• Independent variable


  The variable which quantities are manipulated by the researcher, assumed to have a direct effect on the dependent variable
• Dependent variable


  The variable the researcher measures in an experiment for changes it may experience due to the effect of the independent variable
• Controlled variable


  Variables other than the IV that a researcher holds constant in an investigation
• Extraneous variable


  Any variable that is not the independent variable but may cause an unwanted effect on the dependent variable
• Confounding variable


  A variable that has directly and systematically affected the dependent variable, apart from the independent variable
• Research questions


  Questions that include the IV and DV and are posed as a question
• Aim


  Outlines the purpose of the research, written as a statement
• Hypotheses


  A prediction or an educated guess about the relationship between two variables in an experiment, written as statements
• Research hypothesis


  A testable prediction of the relationship between two variables, outlining how the independent variable is expected to affect the dependent variable
• Research hypothesis consists of

  • Two or more conditions of the IV
  • DV
  • The direction of the expected change
• Case study


  An investigation of a particular activity, behaviour, event or problem that includes complexities encountered in the real world
• Classification and identification


  The arrangement of phenomena, objects or events into manageable sets
• Controlled experiment


  An experimental investigation of the relationship between one or more independent variables and a dependent variable, controlling all other variables
• Correlational study


  Planned observation and recording of events and behaviours that have not been manipulated or controlled
• Fieldwork


  Based on inquiry or investigation of an issue, involving observing and interacting with a selected environment beyond the classroom
• Literature review


  Involves the collation and analysis of secondary data related to other people’s scientific findings and/or viewpoints
• Modelling


  Involves the construction and/or manipulation of a physical or conceptual model that represents a system
• Product, process or system development

  Design or evaluation of an artefact, process or system to meet a human need
• Simulation


  A process of using a model to study the behaviour of a real or theoretical system
• Population


  The wider group of people that a study is investigating
• Sample


  The smaller group of people selected from the population who will be participants in the investigation
• Sample size


  Representative of the population; a large sample size helps ensure representation
• A small sample size may not be representative of the population
• Sampling techniques


  • Random sampling
  • Stratified sampling
• Random sampling


  Every member of the population has an equal chance of being part of the sample
• Random sampling


  • A large enough random sample is likely to be representative of the population
  • Small random samples may not be representative
• Stratified sampling


  • Members of the population are divided into sub-groups and the sample is selected from each sub-group in the same proportion
• Between subjects design


  Each participant is randomly allocated to one of two (or more) entirely separate groups
• Between subjects design


  • Random allocation controls individual participant differences
  • Experiment can usually be completed on one occasion
• Within subjects design


  • Each participant is part of both the experimental group and the control group
  • Groups are identical
• Mixed design


  Combines elements of a between subject design and a within subject design
• Mixed design


  • Difference in participant variables between groups are controlled
  • Can test the effect of multiple independent variables
• Primary data


  Collected directly by the researcher for their own purpose
• Primary data


  • Offers tailored information
  • Little doubt about the quality of data
  • Can be time consuming
• Secondary data


  Collected by someone other than the original researchers
• Secondary data


  • Readily available
  • Can’t guarantee the quality of the data
• Qualitative data


  Text based data recorded from observations or direct interaction with participants
• Qualitative data


  • Detailed and can be open for interpretation
  • Not easy to analyse
  • Time consuming
• Quantitative data


  Numerically based data that can be summarised and analysed statistically
• Quantitative data


  • Easier to present
  • Less time consuming
  • Less detailed