Statistics in Engineering
With examples in MATLAB® and R

Andrew Metcalfe, David Green, Tony Greenfield, Mahayaudin Mansor, Andrew Smith and Jonathan Tuke.


Chapter 5

Data sets


A continuous random variable can be defined in terms of a probability density function (pdf) which is the limit of a histogram as the sample size tends to infinity. One reason for fitting a pdf to data is extrapolation into the tails to estimate probabilities associated with extreme events or to make computer simulations realistic. It is necessary to choose appropriate models for pdfs and a range of distributions that are used in engineering are described: uniform; normal and lognormal; exponential; gamma; and Gumbel. Procedures for fitting these distributions to data are given and a method for the graphical assessment of the goodness of fit is described. Algorithms for the generation of pseudo-random deviates from continuous distributions are explained and implemented with software functions.