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Chapter 7 - Analysing the Data Part IV - Analysis of Variance Chapter 1 - Behavioural Science and research Chapter 2 - Research Design Chapter 3 - Collecting the Data Chapter 4 - Analysing the Data Part I - Descriptive Statistics Chapter 5 - Analysing the Data Part II - Inferential Statistics Chapter 6 - Analysing the Data Part III - Common Statistical Tests Correlation Regression T-tests Chi-squared Readings and links


Chapter 6: Analysing the Data
Part III: Common Statistical Tests


The Z-test

Howell (pp 172-175) discusses the Z-test. The Z-test works in a very similar way to the One Sample T test, except that you know the population standard deviation (sigma ) rather than the sample standard deviation (s). In psychology this is a very rare occurrence. It can occur when we have some well established psychological construct which has been repeatedly assessed with large numbers of people or when a set of scores have been standardised to have a specified mean and specified standard deviation. IQ scores probably fall into this category. However, the vast majority of hypothesis testing carried out in psychology uses the sample data to determine the standard deviation (s) to use in calculations. For the purposes of this unit we will not be discussing the Z-test any further.




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