The authors of the article “Predictive Model for Pitting Corrosion in Buried Oil and Gas...

The authors of the article “Predictive Model for Pitting Corrosion in Buried Oil and Gas Pipelines” (Corrosion, 2009: 332–342) provided the data on which their investigation was based.

a. Consider the following sample of 61 observations on maximum pitting depth (mm) of pipeline specimens buried in clay loam soil.

Construct a stem-and-leaf display in which the two largest values are shown in a last row labeled HI.

b. Refer back to (a), and create a histogram based on eight classes with 0 as the lower limit of the first class and class widths of .5, .5, .5, .5, 1, 2, 5, and 5, respectively.

c. The accompanying comparative boxplot from Minitab shows plots of pitting depth for four different types of soils. Describe its important features.