Theories and HypothesesTheories and Hypotheses

Educational Research

TheoriesTheories

Pulls together results of observations---helps to organize and unify them

Enables one to make general statements about variables and relationships among

TheoriesTheories

Provides information to make specific predictions of research outcomes

Directs and promotes future research

HypothesisHypothesis

A prediction about possible study outcomes

Prediction about how the manipulation of the IV will affect the DV

Derived from theory

Hypothesis Hypothesis

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

ExamplesExamplesA positive relationship exists

between IQ and achievement.The dropout rate is higher for

low SES students than for high SES students.

Suggested Answer to Problem

Suggested Answer to Problem

Clearly statedTestableComes from

research question

PurposesPurposes

tentative explanation of phenomena

relational, testable statementdirection to research

Developing HypothesesDeveloping HypothesesDeductionInduction

THROUGH DEDUCTIONTHROUGH DEDUCTION

General to specificBased on presumed relationships

between variablesBegins with theories

THROUGH INDUCTIONTHROUGH INDUCTION

Specific to generalBegins with specific observationsCombines observations to produce a

general statement--hypothesisExploratory studies

A hypothesis is:A hypothesis is:Based solely on dataRejected or fail to rejectNever proven true or falseSupported or not supported

Types of HypothesesTypes of Hypotheses

Null HypothesisResearch Hypothesis (a) directional (b) nondirectional

Null HypothesisNull HypothesisEmpirical investigations involve

statistical testsNO relationship - NO differenceNegates expectationObserved differences by chanceStatistics determine probability

that null is true

Null Hypothesis ExamplesNull Hypothesis Examples

Nondirective teachers are not more effective than directive teachers.

There will be no difference between boys and girls in math achievement at the middle school level.

More ExamplesMore Examples

There will be no difference in the attendance rate of Caucasians and African-Americans.

Obese people do not eat more than people who are not obese.

Research QuestionResearch Question

Stated as a hypothesis

AdvantagesAdvantages

Forces thinking about outcomeGives direction

Predictions based on evidence - theory

DisadvantagesDisadvantages

May lead to biasMay prevent noticing other phenomena,

results in tunnel vision

Hypotheses may be:Hypotheses may be:

DIRECTIONAL

–Specific direction MADE about study outcome

–assumes what will happen in study

Directional HypothesisDirectional Hypothesis

Directional ExampleDirectional Example

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

Directional ExampleDirectional Example

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

Directional ExampleDirectional Example

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:Hypotheses may be:

–NONDIRECTIONALSpecific prediction NOT MADE about study outcome

Assumes that a difference will be present, but does not place a direction on difference

Nondirectional ExamplesNondirectional ExamplesIndividuals whose meals consist

of items from all the basic food groups will have a DIFFERENT body fat content than individuals who are vegetarians.

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

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

RELATIONSHIP OF RESEARCH QUESTIONS,

RESEARCH HYPOTHESES, AND

NULL HYPOTHESES

Research Question: What is the effect of a mainstreaming workshop on the attitudes of teachers toward mainstreaming?

Research Hypothesis: Teachers’ attitudes toward mainstreaming will improve as a result of attending a workshop on mainstreaming.

Null Hypothesis: There will be no difference in teachers’ attitudes toward mainstreaming measured before a workshop on....

Research Question: Is there a relationship between teachers’ attitudes toward the curriculum and student achievement?

Research Hypothesis: There will be a positive relationship between teachers’ attitudes toward the curriculum and student achievement.

Null Hypothesis: There will be no relationship between teachers’ attitudes toward the curriculum and student achievement.

Testing HypothesesTesting HypothesesRelationship(s) statedNull hypothesis statedMethod of Analysis selectedData--gathered and analyzedDoes evidence permit null

rejection?

Confidence LevelConfidence LevelReject or Fail-To-Reject Null–result of statistical treatment–cut-offs for rejection of null

level of confidence at .05 levellevel of confidence at .01 level

TO BE REMEMBEREDTO BE REMEMBERED

A HYPOTHESIS CANNOT BE PROVEN OR DISPROVEN.

A HYPOTHESIS CAN ONLY BE SUPPORTED OR NOT SUPPORTED.