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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 Frequency distributions Central tendancy Variability The normal distribution Transformations Standard scores - Z scores Correlation and regression Linear regression Readings and links

 

Chapter 4: Analysing the Data
Part II : Descriptive Statistics

 

Normalising

A common requirement for parametric tests is that the population of scores from which the sample observations came should be normally distributed. While many variables are close enough to a normal distribution and many of the tests that we will encounter are quite robust to moderate departures, occasionally there is a need to transform a variable so that the requirement of normality is better met. Essentially this means transforming the distribution such that the symmetry of the distribution is made to resemble a normal distribution more closely.

Howell describes transformations on pages 323-329. You only need to understand the principles behind such transformation and the names of some of the main ones such as the logarithmic, reciprocal, and square root transformations. Assignment I asks you to look more closely at some transformations.

 

 

 

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