Post on 27-Dec-2015
6. Survey and Sampling
When and why are surveys used in behavioral research?
What are the advantages and disadvantages of using interviewsversus questionnaires in survey research?
How is probability sampling used to ensure that a sample is representative of the population?
What is sampling bias, and how does it undermine a researcher’sability to draw conclusions about surveys?
What statistical procedures are used to report and display datafrom surveys?
What is the margin of error of a sample?
Survey:A series of self-report measures, administered either through an interview or a written questionnaire. It aims at producing a “snapshot” of the opinions, attitudes, or behaviors of a group of people at a given time.
Survey
Interview Questionnaire
Do you use free format?
UnstructuredInterview
Structured Interview
Do you meet (call) participants or mail them? Do you focus on a small group or large samples?
Do you create questionnaire?
Survey ofYour originalQuestionnaire
Survey ofExisting Data
Meet a small group Mail large samples
Yes No Yes No
Interviews
Interviews allow the researcher to develop a close rapport and sense of trust with the respondents
X Face to face interviews are extremely expensive to conduct.Alternative: telephone interview
The research method in which researcher ask questions to respondents generally in a face-to-face setting.
The researcher generally uses fixed-format items and reads the questions to the respondents. It allows better comparison of the responses across different individuals.
Unstructured Interview
Structured Interview
The researcher uses either free-format or semi-fixed-format self-report measure. It provides in-depth information about the particular concerns of an individual. However, the interviewers need to be well trained so that they can collect certain information through free conversation. It is also difficult to maintain objectivity.
Focus Group: Shared ideas both with interviewer and respondents.
Questionnaires
A set of fixed-format, self-report items that is completed by respondents at their own pace, often without supervision.
Generally cheaper than interviews because the researcher mails the questionnaire or has them complete the questionnaire in large group.
The respondent may misunderstand the questions.The respondents may ask another person to answer the questions.
X
Use of Original Questionnaire
The Response Rate
Discussion: How can we got more responses?
The Question Order
e.g. Norbert et al (1999) Happiness??
e.g. Kitayama, Karasawa, and Masuda (1995)The Survey of the Earthquake Perception
Discussion: How can we cope with this problem?
Use of Existing Survey Data
Assignment#4: Finding useful database for your research.
e.g. The U.S. Census (General Social Survey)
1. Go to http://www.icpsr.umich.edu 2. With your group members, find one of the research domains which you think interesting.3. Open the abstract (AB) of each database and summarize them4. Discuss what kind of research is possible with these datasets.5. Report what you discussed in the class.
Sampling and Generalization
Sampling: The selection of people to participate in a research project, usually with the goal of being able to use these people to make inferences about a larger group of people.
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Population
Sampling
How do you collect samples?1. Define the Population (e.g. Average American Collage Students)
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2. Consider Representative Samples in the group.
Probability Sampling:
A sampling procedure ensuring that each person in the population has a known chance of being selected to be a part of sample.
3. Decide Sampling Methods
Non Probability SamplingA sampling procedure used in cases where probability sampling is impossible because there is no available frame.
e.g. homeless people
Sampling Bias
Simple Random
Sampling
Systematic Random Sampling
Stratified
Sampling
Cluster
Sampling
Probability Sampling
Proportionate StratifiedSampling
DisproportionateStratifiedSampling
Sampling
Non-ProbabilitySampling
Snowball
Sampling ConvenientSampling
Do you know the populationThat you want to sample? Yes
No
Do you run experiment, setting up the time?
Yes No
Do you have lists? No
Yes
Is the list already random? Are there subgroups in the list?
Yes
No
YesNo
Proportionate?
No Yes
Simple Random Sampling
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In case each person in the population has an equal chance of being selected to be in the sample, the researcher uses random numbers to collect samples. (See Appendix E, Statistical Table 2)
When you use SPSS,
1.Go to “Data” menu2.Click “Select Cases” 3.Choose “Random Sample of Cases”4.Click “Sample”5.Enter exact number that you want to sample and the total number of the data.
Systematic Random Sampling
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In case the sampling frame is itself known to be in a random sequence, then the researcher randomly chooses the first sample and then add certain stable numbers to get the next sample.
Stratified Sampling
Proportionate Stratified Sampling
Disproportionate Stratified Sampling
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In case there are some subgroups in the sampling frame, the researcher breaks the frame into subgroups (strata), and randomly samples in each subgroups.
Oversampling
Cluster Sampling
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In case there is no complete sampling frame, the researcher breaks the possible “population” into a set of smaller groups (called clusters) for which there are sampling frames and then to randomly chooseSome of the clusters for inclusion in the sample.
CT MA ME NH
RI VT NJ NY PA IA
IL IN KS MI MN MO
NB ND OH SD WI CA OR WA
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AR LA OK TX AL DE
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AZ CO ID MT NM NV UT WY
New England
CT MAME
RI VTNY NJ PA
Mid-Atlantic
Midwest
USA
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AL DE FL GA KY MD MS NC SC TN WV VA
South
CA OR WA
Pacific
AR LA
OK TX
Southwest
MSU UM EMUCMUWMU
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Snowball Sampling
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The researcher contacts one or more individuals from the population, and these individuals are used to lead the researcher to other population members.
Convenient Sampling
Experiment 3819/22/001:00_______________
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The researcher samples whatever individuals were readily available without any attempt to make the sample representative of a population. Commonly used in experimental design.