What is Correlational Research

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What is Correlational Research?
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Correlational Research

• Correlational research attempts to determine
  whether, and to what degree, a relationship
  exists between two or more quantifiable
  variables.
• The purpose of correlational study may be to
  establish relationship (or lack of it) or to use
  relationships in making predictions.

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Examples of Correlational Studies

• 1. The relationship between intelligence and
  self-esteem.
• 2. The relationship between anxiety and
  achievement.
• 3. Use of an aptitude test to predict success in
  an algebra course.
• (Show how you will correlate the scores in each
  of the studies).

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Group Comparison Studies

• Examines how the values associated with a single
  variable may be distributed differently among two
  or more groups of people.
• EXAMPLE How do the self-concepts of special
  education children who have been mainstreamed
  differ from the self-concepts of special
  education children in self-contained classrooms?
  (Which is the variable and which are the two
  groups?)

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GROUP WORK

• Give an example of group comparison studies.
  Identify the variable that can take on one of two
  values.

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Formation of Groups in Group Comparison Studies
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Populations, Samples, and Subjects

• Populations are groups consisting of all people
  to whom researchers wish to apply their findings.
• Samples are groups of people (representing
  subsets of populations) from whom data are
  collected.
• Subjects are individuals who participate in a
  research study or people from whom data are
  collected.

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The Target Population and the Accessible
Population

• Target population--the population the researcher
  would like the results to be generalized.
• Accessible population--the population available
  from which the researcher can select.

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GROUP WORK

• Choose a research question and identify (a) the
  target population and (b) accessible population.

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List examples of research populations and samples

• . In the United States
• 2. Oregon
• 3. Washington County
• 4. In Forest Grove
• 5. In Pacific University
• 6. EDUC 601 class.

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Purpose of Sampling

• The purpose of sampling is to obtain a group of
  subjects who will be representative of the larger
  population or will provide specific information
  needed.

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Sampling

• 1. Probability Sampling--selecting a sample that
  will adequately represent the true population.
• (a) Random Sampling--each member of the
  population has the same probability of being
  selected.

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Sampling (cont.)

• (b) Systematic Sampling--every Nth member of the
  population is selected
• (c) Stratified Sampling--subjects are selected
  from groups of the population
• (c) Cluster Sampling--Naturally occurring groups
  are selected

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Example of a Study using Probability Sampling

• What is the attitude of teachers in the North
  Country toward unions?
• 1. The population is 5,000 teachers.
• 2. The desired sample size is 10 of the 5,000
  teachers, or 500 teachers.
• 3. We have a directory which lists all teachers
  in the system.
• RANDOM SAMPLING--

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Steps in SYSTEMATIC SAMPLING

• 1. The population is all 5,000 teachers.
• 2. The desired sample is 500.
• 3. You have a directory which lists all the
  teachers in alphabetical order.
• 4. Nth is equal to the size of the population,
  5,000 divided by the size of the sample. Thus Nth
  (5,000 divided by 500) 10.
• 5. Select a random name at the top of the list of
  teachers.

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Steps (cont.)

• 6. From that point, every following 10th name is
  in the sample.

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Steps in STRATIFIED SAMPLING

• 1. The population is all 5,000 teachers.
• 2. Desired sample size is 10 of the 5,000
  teachers, or 500 teachers.
• 3. The variable of interest is teaching level and
  there are three subgroups--elementary, junior
  high, and senior high.
• 4. Randomly select 10 of each subgroup to
  represent each teaching group proportionally.

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Steps in CLUSTER SAMPLING

• 1. The population is all 5,000 teacher.
• 2. The desired sample size is 500.
• 3. A logical cluster is a school.
• 4. You have a list of all the schools in the
  North Country they are 100 schools.
• 5. There is an average of 50 teachers per school.

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• 6. The number of clusters (schools) needed equals
  the desired sample size, 500, divided by the
  average size of a cluster, 50. Thus, the number
  of schools needed is 500 divided by 50 10.
• 7. Therefore, 10 of the schools are randomly
  selected.
• 8. All the teachers in each of the 10 schools are
  in the sample (10 schools, 50 teachers per
  school, equals the desired sample.

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Steps (cont.)

• 2. Nonprobability Sampling--probability of
  selection unknown.
• (a) Convenience Sampling--a group of subjects
  selected because of availability
• (b) Purposive Sampling--selection of particularly
  informative or useful subjects.
• (c) Quota Sampling--nonrandom sampling
  representative of a target population.

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• 3. Volunteer Samples--asking for volunteers.

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Steps (cont.)

• Research Problems
• Research Questions
• Statement of Purpose

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RESEARCH PROBLEMS

• A Research Problem is a clear, concise statement
  of the purpose of a research investigation.
• 1. It provides a focus for the researcher.
• 2. It gives the reader and user of research
  important information--it helps the reader to
  decide if the research is important or
  interesting and makes the research much easier to
  understand.

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Sources for Research Problems

• 1. Investigators interests and experiences.
• 2. Applying theories.
• 3. Replication.
• 4. Clarification of contradictory results.

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The following topics are nonresearchable. Reframe
them to become researchable

• 1. Should we teach sex education in elementary
  schools?
• 2. Do teachers need to have courses in test
  construction?
• 3. Should the school day be longer?
• 4. Should learning disabled students be
  mainstreamed in English as well as in physical
  education?

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Criteria for evaluating research problems

• 1. The problem must be researchable.
• 2. The problem must be important.
• 3. The problem should indicate the type of
  research.
• 4. The problem should specify the type of
  population.
• 5. The problem should specify the variables.
• 6. The problem should be clear.

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HYPOTHESES

• Hypotheses are educated guesses or tentative
  expectations about a correct solution to a
  problem, descriptions, possible relationships, or
  differences.

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Types of Hypotheses

• 1. Research (or Substantive) Hypothesis--A
  declarative statement of the results the
  investigator expects to find.
• 2. Null (or Statistical) Hypothesis--Is a
  statement of a relationship or difference that
  can be tested statistically.

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• Try to do a research in your own classroom using
  any of the quantitative research methods.