What is Correlational Research?

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.

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).

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?)

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

Formation of Groups in Group Comparison Studies

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.

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.

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

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.

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.

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.

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

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--

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.

Steps (cont.) 6. From that point, every following 10th name is in the sample.

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.

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.

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.

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.

3. Volunteer Samples--asking for volunteers.

Steps (cont.) Research Problems Research Questions Statement of Purpose

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.

Sources for Research Problems 1. Investigator’s interests and experiences. 2. Applying theories. 3. Replication. 4. Clarification of contradictory results.

The following topics are nonresearchable 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?

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.

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

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.

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