Lesson 10: Research Methods                               Sampling                                  &                     ...
Lesson 9Exam Question                          2012 VCAA ExamMonday, 14 January 2013
Question                          A   B   C   DMonday, 14 January 2013
OUTCOMES:                        Define population                           Define sample     Describe the process of sampl...
Sampling                Sampling is the selection of participants for a                research.                Population...
Representative Samples                          Two techniques are used to                          ensure a representativ...
Random Sample                          A sampling procedure in which every member                          of the populati...
Stratified Sampling and Stratified                              Random Sampling          Is used when you wish to          e...
Activity:                          Stratified Random SamplingMonday, 14 January 2013
Participant Allocation: Experimental &                             Control Groups            The experimental method uses ...
Experimental and Control Group Allocation             It is super important that all participants have an             equa...
Experimental Designs                          There are three popular experimental                          designs       ...
Repeated Measures Design                          (within participants design)      •      In a repeated measures design a...
What are the advantages of repeated measures design?                          What are the limitations (disadvantages)?Mon...
Matched Participants Design      •       Enables the researcher to identify a variable that is likely confound and to     ...
•      For example      •      A sports coach developed a new game plan that would help             the team reach the pla...
What are the advantages of matched participants design?                          What are the limitations (disadvantages)?...
Independent Groups Design                          (between participants design)       •      Allocates participants to th...
What are the advantages of independent groups design?                          What are the limitations (disadvantages)?Mo...
Participants       This may effect the DV               expectations      resulting in invalid results                    ...
For example: Experimenter treats             Experimenter        participants differently depending on               influe...
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Lesson 10 research methods sampling and experimental design 2013

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Lesson 10 research methods sampling and experimental design 2013

  1. 1. Lesson 10: Research Methods Sampling & Experimental DesignMonday, 14 January 2013
  2. 2. Lesson 9Exam Question 2012 VCAA ExamMonday, 14 January 2013
  3. 3. Question A B C DMonday, 14 January 2013
  4. 4. OUTCOMES: Define population  Define sample Describe the process of sampling procedures including random, stratified and random stratified Describe the process of participate allocation to groups (experimental and control) including random allocation Discuss the advantages and disadvantages of different experimental designs including repeated measures, matched participants and independent groups  Describe the placebo effect and ways of managing its occurrence Describe the experimenter effect and ways of managing its occurrence   Monday, 14 January 2013
  5. 5. Sampling Sampling is the selection of participants for a research. Population refers to the group which the research wishes to draw conclusions from. The term sample refers to the members of the population that have been chosen to take part in the research. Sampling procedures must ensure that the sample is representative of the population.Monday, 14 January 2013
  6. 6. Representative Samples Two techniques are used to ensure a representative sample: 1)Random Sampling 2)Stratified Sampling and Stratified Random Sampling.Monday, 14 January 2013
  7. 7. Random Sample A sampling procedure in which every member of the population has an equal chance of being selected Examples include: 1) Picking a name out of a hat 2) Tattslotto 3) Closing my eyes and selecting a number to match that number with student id numbers.Monday, 14 January 2013
  8. 8. Stratified Sampling and Stratified Random Sampling Is used when you wish to eliminate the effects of confounding variables. The effects of a certain variable can be eliminated as a possible confounding variable in an experiment. The variable could be any personal attribute, such as age, years of education, ethnicity, gender, IQ etc.Monday, 14 January 2013
  9. 9. Activity: Stratified Random SamplingMonday, 14 January 2013
  10. 10. Participant Allocation: Experimental & Control Groups The experimental method uses two different groups called the experimental and control groups. The experimental group are exposed to the IV, known as the ‘treatment’. The control group do not receive the treatment (IV). The purpose of the experimental group is to show the effects of the IV on the value of the DV. The purpose of the control group is to form a basis for comparison with the experimental group.Monday, 14 January 2013
  11. 11. Experimental and Control Group Allocation It is super important that all participants have an equal chance of being in the experimental or control group. That is Random Allocation. When there is a large enough sample, both the experimental and control groups will be equivalent on all participant characteristics therefore the presence or absence of the IV is the only difference between them. E.G. If we had all males in the experimental group and all females in the control group, then an obvious extraneous variable will be gender.Monday, 14 January 2013
  12. 12. Experimental Designs There are three popular experimental designs Repeated Measures Design Matched Participants Design Independent Groups DesignMonday, 14 January 2013
  13. 13. Repeated Measures Design (within participants design) • In a repeated measures design all participants experience both the experimental and control groups. • This is possible by conducting the experiment on two occasions and then comparing the two results.Monday, 14 January 2013
  14. 14. What are the advantages of repeated measures design? What are the limitations (disadvantages)?Monday, 14 January 2013
  15. 15. Matched Participants Design • Enables the researcher to identify a variable that is likely confound and to eliminate the effects of this variable from the experiment. • Participants can be ranked in accordance with their scores on this variableMonday, 14 January 2013
  16. 16. • For example • A sports coach developed a new game plan that would help the team reach the playoffs. He decided to test this by giving the experimental group the instruction but not the control group. Because individual skills would be a confounding variable, he decided to ‘match’ the groups. The two highest skilled players will be randomly allocated to either the experimental or control group, the third and fourth most skilled will then be randomly allocated to either and so on and so forth until all players were allocated to a group resulting in the same mean skill percentage in both groups.Monday, 14 January 2013
  17. 17. What are the advantages of matched participants design? What are the limitations (disadvantages)?Monday, 14 January 2013
  18. 18. Independent Groups Design (between participants design) • Allocates participants to the experimental or control group at randomMonday, 14 January 2013
  19. 19. What are the advantages of independent groups design? What are the limitations (disadvantages)?Monday, 14 January 2013
  20. 20. Participants This may effect the DV expectations resulting in invalid results PLACEBO EFFECT Can be eliminated by using single blind procedure, that is participants are unaware of which group they are in.Monday, 14 January 2013
  21. 21. For example: Experimenter treats Experimenter participants differently depending on influences the group they are in which in turn experiment influences the behaviour of the participant and effects the results EXPERIMENTER EFFECT Can be eliminated by using a double blind procedure, that is, neither the experimenter or the participants are aware of whether they are in the experimental or control groupMonday, 14 January 2013

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