Causal HypothesesCausal HypothesesCausal HypothesesCausal Hypotheses

Causal HypothesesCausal HypothesesCausal HypothesesCausal Hypotheses

Statement of relationship between an Statement of relationship between an independent and dependent variableindependent and dependent variable

Describes a cause and effectDescribes a cause and effect Usually stated in two formsUsually stated in two forms

The null hypothesisThe null hypothesis The alternative hypothesisThe alternative hypothesis

The two forms areThe two forms are Mutually exclusiveMutually exclusive ExhaustiveExhaustive

Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)

Employee training program will reduce Employee training program will reduce employee absenteeism.employee absenteeism.

There will be There will be no change no change or there will be or there will be moremore absenteeism as a result of training.absenteeism as a result of training.

There will be There will be lessless absenteeism as a result of absenteeism as a result of training.training.

Causal hypothesisCausal hypothesisCausal hypothesisCausal hypothesis

Alternative:Alternative:Alternative:Alternative:

Null:Null:Null:Null:

Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)

Employee training program will reduce Employee training program will reduce employee absenteeism.employee absenteeism.

There will be There will be no change no change or there will be or there will be moremore absenteeism as a result of training.absenteeism as a result of training.

There will be There will be lessless absenteeism as a result of absenteeism as a result of training.training.

Causal hypothesisCausal hypothesisCausal hypothesisCausal hypothesis

Alternative:Alternative:Alternative:Alternative:

Null:Null:Null:Null:

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No changeNo change

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AbsenteeismAbsenteeism

Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)Causal Hypothesis (One-Tail)

Employee training program will reduce Employee training program will reduce employee absenteeism.employee absenteeism.

There will be There will be no change no change or there will be or there will be moremore absenteeism as a result of trainingabsenteeism as a result of training..

There will be There will be lessless absenteeism as a result of absenteeism as a result of training.training.

Causal hypothesisCausal hypothesisCausal hypothesisCausal hypothesis

Alternative:Alternative:Alternative:Alternative:

Null:Null:Null:Null:

A “one-tail” hypothesisA “one-tail” hypothesis

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No changeNo change

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AbsenteeismAbsenteeism

Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)

Our new drug treatment will cause a difference Our new drug treatment will cause a difference in depression.in depression.

There will be There will be no change no change in depression as a in depression as a result of treatment.result of treatment.

There will be There will be a change a change in depression as a in depression as a result of treatment.result of treatment.

Causal hypothesisCausal hypothesisCausal hypothesisCausal hypothesis

Alternative:Alternative:Alternative:Alternative:

Null:Null:Null:Null:

Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)

Our new drug treatment will cause a difference Our new drug treatment will cause a difference in depression.in depression.

There will be There will be no change no change in depression as a in depression as a result of treatment.result of treatment.

There will be There will be a change a change in depression as a in depression as a result of treatment.result of treatment.

Causal hypothesisCausal hypothesisCausal hypothesisCausal hypothesis

Alternative:Alternative:Alternative:Alternative:

Null:Null:Null:Null:

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No changeNo change

LessLess MoreMore

DepressionDepression

Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)Causal Hypothesis (Two-Tail)

Our new drug treatment will cause a difference Our new drug treatment will cause a difference in depression.in depression.

There will be There will be no change no change in depression as a in depression as a result of treatmentresult of treatment..

There will be There will be a change a change in depression as a in depression as a result of treatment.result of treatment.

Causal hypothesisCausal hypothesisCausal hypothesisCausal hypothesis

Alternative:Alternative:Alternative:Alternative:

Null:Null:Null:Null:

A “two-tail” hypothesisA “two-tail” hypothesis

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No changeNo change

LessLess MoreMore

DepressionDepression