Hydro-Mechanical Properties of an Unsaturated Frictional Material

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CHAPTER 3. INTRODUCTION TO PROCESS MODELING - A STATISTICAL
APPROACH
of few points far from the line could be outliers. Compared to the histogram the normal
probability plot is conveniently used to discern deviations from normality.
- Histogram:
Similar to the normal probability plot the histogram is used to check the normal distri-
bution of the analyzed data set. Histograms summarize the distribution of a data set
and shows the location (i.e. center), the scale (i.e. spread), the skewness of the data
and the presence of outliers. Compared to the normal probability plot a histogram of
the residuals of the fit provides a detailed picture of the shape of the distribution. More
or less bell shaped histograms confirm conclusions of a normally distributed data set.
3.3 Summary
A method for model building for determination of soil-water characteristic curve using data
transformation was introduced in the present chapter, that is based on statistical analysis.
The data transformation is used to find linear relation, that gives the possibility to use
linear regression. In detail the steps for model building are given and described. The method
presented above will be used later for developing soil-water characteristic curve model for
Hostun sand, that includes prediction of drainage as well as imbibition process.