Outline Research Methods Lecture 4

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Cory Farmer
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1 Outline Research Methods Lecture 4 Basic Building Blocks of Research Basic components of a study Classifications of research categorization of variables Measures Validity and reliability Sampling processes Classifications of Research Basic vs. Applied research Laboratory vs. Field research Experimental vs. Non-experimental research Classifications of Research Experimental vs. Non-experimental subtypes of non-experimental designs Observation studies Case studies Survey (interview, phone, mailing, etc.) Archive studies Variable e.g., there is an association What is a variable? any attribute or property in which organisms (people, objects, events) vary. 1

2 Independent (IV) vs. dependent variable (DV) the effect of X on Y X = independent, the factor of interest, could be manipulated, presumed cause Y = dependent, outcome, not manipulated manipulated vs. subject variables example: manipulated variables Subject variables Causal inference and subject variables example: Anxiety level High Low performance on interviews Qualitative vs. Quantitative variables discrete (categorical) vs. continuous variable Qualitative levels of a variable differ in kind Quantitative levels of a variable differ in amount or degree Latent (unobserved) vs. Observed variables Latent variable it cannot be observed directly but is nonetheless thought to be exist and to cause the manifestations of observed variables Singh s waist-to-hip ratio study IV: DV: Pennebaker s writing study Schachter and Singer s study Happy No emotional change Informed Angry No emotional change Traumatic Trivial Number of visits to campus health center Not informed Happy Angry Feel happy Feel angry 2

3 Dutton and Aron s transfer of excitation Swinging Bridge Plain bridge Female Experimenter Evaluating Attractiveness Defining variables there is an association between depression and academic Conceptual definition Depression a feeling of sadness, a feeling of unhappiness, loneliness, or no hope for the future Operational definition Bridgman (1927) all concepts should be defined in terms of a set of operations to be performed. e.g., Hunger Sleep deprivation How about depression? Measures Hypothesis: there is an association IV = DV = could be the other way, based on the matter of interest. However, sometimes, it should be fixed How to measure the IV and the DV? Evaluating Measures Two criteria reliability and validity Reliability refers to the consistency of a measure e.g., weight scale Validity refers to whether we have measured what we have intended to measure e.g., academic achievement and GPA academic achievement and a number of computers at home Evaluating Measures Relationship between reliability and validity Reliability is a necessary but not a sufficient condition for validity. 3

4 Evaluating Measures Depression Clinical interview, Beck Depression Inventory (BDI) Academic achievement SAT scores, GPA, grades, exam scores Population vs. Sample Hypothesis: there is an association Population a complete set of individuals having some common observable characteristics e.g., all CSUN students all U.S.citizens Sample a subset of a population Population vs. Sample Goal of research draw a conclusion about a population on the basis of a sample. Representative sample reflects the attributes of the population as a whole Biased sample Two processes of sampling Probability sampling simple random sampling stratified sampling cluster sampling Non-probability sampling convenience sampling snowball sampling Two processes of Sampling Simple random sampling - each member of the population has an equal chance of being selected as a member of the sample - limitations: 1) when we should consider certain characteristics of a population related to a research question Probability sampling Stratified sampling - the proportions of important subgroups in a population are represented precisely in the sample 2) too expensive or impractical 4

5 Probability sampling Cluster sampling - randomly selects a cluster of people all having some features in common Non-probability sampling Convenience sampling - volunteers from a group of available people who meet the general requirements of the study Snowball sampling - recruit individuals closely related to a research topic and ask them for others to contact Steps in the Research Process Research Designs Get an idea Review the literature Plan a study Conduct the study Hypothesis Measures Sampling Design a study Analyze data Write a paper Present the study Non-experimental Methods Observational research Case / Small N study Survey Research Archival Research Quasi-Experimental Designs Experimental Methods Single-factor Designs Repeated Measures Designs Factorial Designs 5

Sampling. COUN 695 Experimental Design

Sampling. COUN 695 Experimental Design Sampling COUN 695 Experimental Design Principles of Sampling Procedures are different for quantitative and qualitative research Sampling in quantitative research focuses on representativeness Sampling