Theories and Hypotheses Educational Research

Theories H Pulls together results of observations---helps to organize and unify them H Enables one to make general statements about variables and relationships among

Theories H Provides information to make specific predictions of research outcomes H Directs and promotes future research

Hypothesis H A prediction about possible study outcomes H Prediction about how the manipulation of the IV will affect the DV H Derived from theory

Hypothesis H sets forth an anticipated relationship between two (or more) variables

Examples H A positive relationship exists between IQ and achievement. H The dropout rate is higher for low SES students than for high SES students.

Suggested Answer to Problem H Clearly stated H Testable H Comes from research question

Purposes H tentative explanation of phenomena H relational, testable statement H direction to research

Developing Hypotheses H Deduction H Induction

THROUGH DEDUCTION H General to specific H Based on presumed relationships between variables H Begins with theories

THROUGH INDUCTION H Specific to general H Begins with specific observations H Combines observations to produce a general statement--hypothesis H Exploratory studies

A hypothesis is: H Based solely on data H Rejected or fail to reject H Never proven true or false H Supported or not supported

Types of Hypotheses H Null Hypothesis H Research Hypothesis H (a) directional H (b) nondirectional

Null Hypothesis H Empirical investigations involve statistical tests H NO relationship - NO difference H Negates expectation H Observed differences by chance H Statistics determine probability that null is true

Null Hypothesis Examples H Nondirective teachers are not more effective than directive teachers. H There will be no difference between boys and girls in math achievement at the middle school level.

More Examples H There will be no difference in the attendance rate of Caucasians and African-Americans. H Obese people do not eat more than people who are not obese.

Research Question H Stated as a hypothesis

Advantages H Forces thinking about outcomeGives direction H Predictions based on evidence - theory

Disadvantages H May lead to bias H May prevent noticing other phenomena, results in tunnel vision

Hypotheses may be: H DIRECTIONAL –Specific direction MADE about study outcome –assumes what will happen in study

Directional Hypothesis

Directional Example HIGHER –Individuals who smoke will have a HIGHER incidence of respiratory illnesses than individuals who do not smoke.

Directional Example H Students who read below grade level will find school less pleasant than those students who read at or above grade level.

Directional Example H A combination of reading readiness training and programmed reading instruction will be more effective in teaching reading than normal classroom instruction in sight reading.

Hypotheses may be: –NONDIRECTIONAL ‡ Specific prediction NOT MADE about study outcome ‡ Assumes that a difference will be present, but does not place a direction on difference

Nondirectional Examples H Individuals whose meals consist of items from all the basic food groups will have a DIFFERENT body fat content than individuals who are vegetarians.

H The IQs of boys enrolled in the preschool intervention program will be different from the IQs of girls enrolled in the preschool intervention program.

H The attitudes of teachers who attended the At-Risk workshop will be different from the attitudes of teachers who did not attend the At-Risk workshop.

RELATIONSHIP OF RESEARCH QUESTIONS, RESEARCH HYPOTHESES, AND NULL HYPOTHESES

H Research Question: What is the effect of a mainstreaming workshop on the attitudes of teachers toward mainstreaming? H Research Hypothesis: Teachers’ attitudes toward mainstreaming will improve as a result of attending a workshop on mainstreaming. H Null Hypothesis: There will be no difference in teachers’ attitudes toward mainstreaming measured before a workshop on....

H Research Question: Is there a relationship between teachers’ attitudes toward the curriculum and student achievement? H Research Hypothesis: There will be a positive relationship between teachers’ attitudes toward the curriculum and student achievement. H Null Hypothesis: There will be no relationship between teachers’ attitudes toward the curriculum and student achievement.

Testing Hypotheses H Relationship(s) stated H Null hypothesis stated H Method of Analysis selected H Data--gathered and analyzed H Does evidence permit null rejection?

Confidence Level H Reject or Fail-To-Reject Null –result of statistical treatment –cut-offs for rejection of null ‡ level of confidence at.05 level ‡ level of confidence at.01 level

TO BE REMEMBERED H A HYPOTHESIS CANNOT BE PROVEN OR DISPROVEN. H A HYPOTHESIS CAN ONLY BE SUPPORTED OR NOT SUPPORTED.