Permeability of sandstone during weathering. Refer to the Geographical Analysis (Vol...

Permeability of sandstone during weathering. Refer to the Geographical Analysis (Vol. 42, 2010) study of the decay properties of sandstone when exposed to the weather, Exercise 2.69 (p. 63). Recall that slices of sandstone blocks were tested for permeability under three conditions: no exposure to any type of weathering (A), repeatedly sprayed with a 10% salt solution (B), and soaked in a 10% salt solution and dried (C). Measures of variation for the permeability measurements (mV) of each sandstone group are displayed in the accompanying MINITAB printout.

a. Find the range of the permeability measurements for group A sandstone slices. Verify its value using the minimum and maximum values shown on the printout.

b. Find the standard deviation of the permeability measurements for group A sandstone slices. Verify its value using the variance shown on the printout. 14.48

c. Which condition (A, B, or C) has the more variable permeability data? B

REFERENCE: Exercise 2.69

Permeability of sandstone during weathering. Natural stone, such as sandstone, is a popular building construction material. An experiment was carried out in order to better understand the decay properties of sandstone when exposed to the weather (Geographical Analysis, Vol. 42, 2010). Blocks of sandstone were cut into 300 equal-sized slices and the slices randomly divided into three groups of 100 slices each. Slices in group A were not exposed to any type of weathering; slices in group B were repeatedly sprayed with a 10% salt solution (to simulate wetting by driven rain) under temperate conditions; and slices in group C were soaked in a 10% salt solution and then dried (to simulate blocks of sandstone exposed during a wet winter and dried during a hot summer). All sandstone slices were then tested for permeability, measured in milliDarcies (mD). These permeability values measure pressure decay as a function of time. The data for the study (simulated) are saved in the SAND file. Measures of central tendency for the permeability measurements of each sandstone group are displayed in the MINITAB printout on p. 64.