Upcoming SlideShare
×

# Lesson 10 research methods sampling and experimental design 2013

6,914

Published on

3 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

Views
Total Views
6,914
On Slideshare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
126
0
Likes
3
Embeds 0
No embeds

No notes for slide

### 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
1. #### A particular slide catching your eye?

Clipping is a handy way to collect important slides you want to go back to later.