Experimental research involves deliberately influencing a variable to test cause and effect relationships using experimental and control groups randomly assigned subjects. Quantitative research methodologies also include correlational research which examines relationships between variables, causal-comparative research which determines causes or consequences of pre-existing differences, survey research which collects information from a sample using questionnaires, and single subject research which collects data from one subject at a time. Proper research design, sampling, instrumentation, and data analysis are important for validity.

1. Quantitative Research Methodologies

2. Experimental Research This is a type of research that deliberately attempts to influence a particular variable and when properly applied is the best type of testing the cause and effect relationshipsIt involves two groups: the experimental group which receives a treatment of some sort and a control group which receives no such treatment

3. Randomization Subjects are randomly assigned to the various groups in the experimental studyHolding variables constantBuilding the variable in to the designMatchingUsing subjects as their own controlsUsing analysis of covariance

4. Weak experimental designOne shot case studyOne group pre-test, post test designStatic group comparison designStatic group pretest, post test design

5. True experimental designRandom post test only control group design

6. Parts of an Experimental ResearchPurpose/Justification – explains the logic of the researchDefinition – are the terms clearly defined?Prior research – any previous work done?Hypothesis – how is it stated?Sample – what type of sample is usedInstrumentation – is it adquately describedProcedures/internal validity – what are the threats evident?Data analysis – are data summarized and reported appropriately?Results – how are they presentedDiscussion/interpretation – do authors place the study in a broader context?

7. Single Subject Research This is a type of research in which data are collected and analyzed for only one subject at a time. It is used to study children with handicaps. It would make little sense to form groups of three each in an instance.Threats include: Condition length is arbitrary. The researcher must determine what time data is sufficient; number of variables change from one condition to another

8. partsPurposeDefinitionLiterature reviewSample/subjectMethod (reward analysis)ExperimentsGeneral discussionConclusion Implication

9. Correlational Research This type of research is carried out for one or two basic purposes. One is to help explain important human behavior or to predict likely outcomes.Here the researcher collects different kinds of data from subjects that might be related to the problemMethods: simple prediction equation (simple graph) Multiple regression (venn diagram)

10. Causal-Comparative ResearchIn causal-comparative research investigators attempt to determine the cause or consequences of differences that already exist between two groups or individuals. (ex post facto research)Examples 1: Type 1 exploration of effects (dependent variable)What are the differences caused by genderResearch hypothesis: females have a greater amount of linguistic abilities than men.

11. ExamplesType 2: exploration of causes (independent variable)Question: What causes individuals to join a gang?Research hypothesis: individuals who are members of gangs have more aggressive personalities than those who are not members of gangs.

12. Type No. 3 Exploration of the Consequences (dependent variable) of an interventionQuestion: how do students taught by the inquiry method react to propaganda?Research Hypothesis: stufdents who were taught by the inquiry method are more critical of propaganda than those taught by the lecture method.

13. Survey ResearchSurvey is used to collect information to describe some aspects or characteristics such as abilities, attitudes, beliefs, and or knowledge of the population of which the group is a part.It is the main way of information is collected by asking questions.Information is collected from a sample rather than from every member of the population.

14. Kinds of surveyCross sectional survey – the researcher collects information from a sample drawn from a predetermined population. When the entire population is surveyed this is called a census.Longitudinal survey – here information is collected in different points in time to study changes over time. Three designs are commonly used: the survey research, trend studies, cohort studies and panel studies

15. Trend studies – different samples are taken from a population whose members may change in time. i.e. Attitudes of principals regarding flexible scheduling during certain parts of the year.Cohort studies – samples in a particular population do not change over the course of the surveyPanel studies – the researcher surveys the same sample of individuals during the course of the survey. I.e. Status of history instruction; dimensions of effective school leadership

16. Type of QuestionsOpen-ended questions allow individual responsesClosed ended questions – allows limited options. Multiple choice questions allow measurement of opinions and knowledge.

17. Bad questionsAmbiguous – do you spend a lot of time studying?Better: how much time do you spend studying? A) 2 hours b) 4 hours c) 6 hours d) more than 7 hours e) neverNo focus: who do you think are more satisfied in teaching elementary and secondary schools, men or womenKeep the question short: what part of the English curriculum in your opinion is the most important in terms of the development of students in the program?Improved: what part of the district’s English curriculum is the most important?Use common language: what do you think is the principal reason that schools are experiencing absenteeism today?Better: What are the causes why more students are absent this year than previously?