planning research part 1 method, participants, instruments & ethics kathy-ann hernandez, ph. d....
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Planning Research Part 1Method, Participants, Instruments & Ethics
Kathy-ann Hernandez, Ph. D.Spring 2007
Participant Selection
Whom to select?
How to select?
How many to select?
Sampling Terms Random sampling/Probability
Every individual in the population of interest has an equal chance of being in the sample
Biased sampling/Non Probability some individuals from the population
of interest have a greater chance of being selected than other individuals
Sampling Procedures Sampling Procedures
Probability/Random Physical Mixing Process Random Number Table Systematic Random Sampling
Non-probability Sampling/non random sampling
Convenience or Accidental Sampling Purposive sampling
Biased Sampling
QL and QN Sampling Procedures
Quantitative Methods Simple Random Sampling Stratified Random Sampling Systematic sampling Cluster Sampling
Qualitative Methods Purposive sampling Criterion sampling
Convenience Sampling
Population vs Sample
Select by physically mixing or use table of random numbers
Stratified Sampling
Stratified random sampling used when we have subgroups in our population that are likely to differ substantially behavior.
Create separate strata and select randomly from each stratum. (gender, age groupings)
Stratified Proportionate Sampling
Proportionate sampling can be used with stratified sampling. Select individuals from each stratum based on the proportion they comprise of the population. Ex. 400 (M) ; 500 (F) - select 10% from each group.
Systematic Sampling
Select every nth person
Cluster Sampling
Cluster sampling is useful when it would be impossible or impractical to identify every person in the sample. Instead of sampling 10% of EU students, sample 10 % of the classes randomly.
Non probability/non random sampling
Convenience or Accidental Selecting a sample because it is easily
accessible and reasonably representative of the population of interest.
Purposive Sampling Handpicked individuals because they have
characteristics of interest
Criterion Sampling Clear criteria established for identifying
participants
Convenience Sampling
Convenience Sampling
Looks like cluster sampling, but clusters are not selected at random
Purposive Sampling
Purposive sampling targets a particular group of people.
Types of Purposive Sampling
Random Purposive Sampling Case sampling
Typical and extreme or deviant
Intensity sampling Maximum Variation sampling Homogenous sampling Opportunistic sampling Stratified Purposive sampling Snowball sampling
Instrumentation
How do I measure my variable of interest?
Where can I find instruments?
Can I create an instrument?
Instruments Use instruments used in Previous
Research Locate instruments from databases
ETS Tests in Print Buros Mental Measurement Yearbook
Begin thinking about creating your own instrument
Issues in Devising New Instruments
QN Validity- accuracy
Judgmental, criterion-related, and construct validity Reliability- consistency
Number of items, correlation coefficients QL
Credibility – accuracy member checks; triangulation of sources
Dependability – control of subjectivity Triangulation of instruments
Handout
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