Research methods

• a hypothesis is a formal and testable statement of the relationship between 2 variables
• types of hypothesis:

  1. directional hypothesis
  2. non-directional hypothesis
  3. null hypothesis
  4. alternative hypothesis
• null hypothesis - a statement that the observed variables will have no impact as there is no relationship between them.
• alternative hypothesis - one variable will have an impact on the other
• directional hypothesis - stating the impact that the variables will have on each other
• non-directional hypothesis - that the variables will have an impact, but not knowing what the impact will be
• types of variables:

  1. independent variable
  2. dependent variable
  3. control variable
  4. extraneous variable
• independent variable - what researchers manipulate to get their results
• dependent variable - the variable that is measured in an experiment
• control variable - the variable that is left alone
• extraneous variable - a variable that is not controlled by the researcher but may affect the results
• types of sampling:

  1. random sampling
  2. opportunity sampling
  3. systematic sampling
  4. stratified sampling
  5. volunteer sampling
• random sampling - involves the researcher identifying members of the population by numbering them and randomly choosing numbers for people to participate
• random sampling:

  strength - unbiased as all members have equal chance

  strength - minimizes chance of researchers influence on results
• random sampling:

  weakness - can still end up with an unrepresentative sample

  weakness - can be time consuming
• opportunity sampling - asking those closest around you to participate in the experiment
• opportunity sampling:

  strength - least time consuming
• opportunity sampling:

  weakness - greater chance of being bias

  weakness - researcher could influence the sampling
• systematic sampling - selecting every 'nth' term of a population
• systematic sampling:

  strength - simple way of researchers gathering participants, little influencing bias
• systematic sampling:

  weakness - could still be un representative of the population

  weakness - requires a large population size
• stratified sampling - sub groups are identified within the population, then people are drawn from each sub-group
• stratified sampling:

  strength - very representative of the population
• stratified sampling:

  weakness - very time consuming
• volunteer sampling - people volunteer to be part of the experiment
• volunteer sampling:

  strength - participants are willing to take part

  strength - can be fast and efficient
• volunteer sampling:

  weakness - the volunteer sample tends to be a bias sample
• experimental designs:

  1. independant groups
  2. repeated measures
  3. matched pairs
• independent groups design - one group takes part in the experimental condition, then one group is kept as a control group and then results between the 2 are compared to show the experiments impact
• independent groups:

  strength - no order effects to impact results

  strength - materials or apparatus ca be used for both groups, easier to set up

  strength - less likely to display demand characteristics
• independent groups:

  weakness - may be differences between people between the groups

  weakness - requires a larger sample
• repeated measures - all participants are exposed to both conditions of the study
• repeated measures:

  strength - require less effort and is faster to set up

  strength - participant variables are eliminated
• repeated measures:

  weakness - high risk of order effects

  weakness - high risk of demand characteristics
• matched pairs - gathering 2 groups of participants who have similar characteristics to each other
• matched pairs:

  strength - can reduce participant variables

  strength - no order effects

  strength - can reuse equipment or apparatus
• matched pairs:

  weakness - difficult to find a sample of the same characteristics

  weakness - difficult to outline wanted characteristics
• experiment settings:

  • lab experiment
  • field experiment
  • natural experiment
• lab experiment - experiment conducted in a controlled setting, usually a lab where participants are aware of the study taking place
• lab experiments:

  strength - have high validity

  strength - limits extraneous variables

  strength - high reliability