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.