Research Methods 2

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Topic 11: The power of a hypothesis test
(Week 12)

Aims

To understand the errors that can be made when using hypothesis tests and to appreciate how these can be controlled

Objectives

To understand the ways in which the results of a hypothesis test can be in error

To know the terms 'Type I error' , 'Type II error' and 'Power'

To know that the power of a test depends on the true difference and the sample size

To appreciate, in qualitative terms, how the idea of power can be used to estimate the number of subjects needed for a study

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This week there is one document to be studied, with an accompanying exercise sheet.

• Study the document  The Power of a Hypothesis Test, which explains the key ideas.
• Answer the questions in Exercise Sheet 1.

{to obtain the macro ttestpow right-click here and choose 'Save Target As...'}

• You should check your answers by referring to the Solutions to Exercise Sheet 1.

Further reading on the topics addressed this week can be found in Bland, chapter 18