based on the evaluation of the respective sample statistics, see Table 2.6. For this set of data
there are no outside values as the upper adjacent value is the maximum value of the data and
the lower adjacent value corresponds to the lower value of the data.
Table 2.6: Statistics for the Tukey box plot for the concrete cube compressive strength data [MPa]
(Table 2.2).
Figure 2.8: Tukey box plot of the concrete cube compressive strength data [MPa].
2.7 Introduction to Engineering Uncertainty Modelling
A central role for engineers is to provide basis for decision making in regard to the cost
efficient safeguarding of personnel, environment and assets in situations where uncertainties
are at hand. A classical example is the decision problem of choosing the height of a dike. The
risk of dike flooding can be reduced by increasing the height of the dike; however, due to the
inherent natural variability in the water level a certain probability of dike flooding in a given
reference period will always remain. Risk assessment within the theoretical framework of
decision analysis can help us in deciding on the optimal dike height by weighing the benefits
of reduced dike flooding risks with the costs of increasing the dike height. However, a
prerequisite for the risk assessment is that the means for assessing the probability of dike
flooding are established, and this in turn requires that a probabilistic model for the future
water level is available.